diff --git a/lib/api/completeMultipartUpload.js b/lib/api/completeMultipartUpload.js
index 88197d1bfc..7f076fef7a 100644
--- a/lib/api/completeMultipartUpload.js
+++ b/lib/api/completeMultipartUpload.js
@@ -1,6 +1,6 @@
 const async = require('async');
 const { parseString } = require('xml2js');
-const { errors, versioning, s3middleware, storage } = require('arsenal');
+const { errors, errorInstances, versioning, s3middleware, storage } = require('arsenal');
 
 const convertToXml = s3middleware.convertToXml;
 const { pushMetric } = require('../utapi/utilities');
@@ -538,11 +538,14 @@ function completeMultipartUpload(authInfo, request, log, callback) {
             services.batchDeleteObjectMetadata(mpuBucket.getName(),
                 keysToDelete, log, err => {
                     if (err) {
-                        // Handle specific error cases according to retry strategy
                         if (err.is?.DeleteConflict) {
                             // DeleteConflict should trigger automatic retry
                             // Convert to InternalError to make it retryable
-                            return next(errors.InternalError, extraPartLocations,
+                            const customErr = errorInstances.InternalError.customizeDescription(
+                                'conflict deleting MPU parts metadata'
+                            );
+
+                            return next(customErr, extraPartLocations,
                                 destinationBucket, aggregateETag, generatedVersionId, droppedMPUSize);
                         }
 
@@ -551,6 +554,7 @@ function completeMultipartUpload(authInfo, request, log, callback) {
                         return next(err, extraPartLocations,
                             destinationBucket, aggregateETag, generatedVersionId, droppedMPUSize);
                     }
+
                     return next(null, extraPartLocations,
                         destinationBucket, aggregateETag, generatedVersionId, droppedMPUSize);
                 });
diff --git a/lib/services.js b/lib/services.js
index ce7c89358b..cbf8740170 100644
--- a/lib/services.js
+++ b/lib/services.js
@@ -985,7 +985,7 @@ const services = {
         assert.strictEqual(typeof mpuBucketName, 'string');
         async.eachLimit(keysToDelete, 5, (key, callback) => {
             metadata.deleteObjectMD(mpuBucketName, key, { overheadField: constants.overheadField }, log, callback);
-        }, err => cb(err));
+        }, cb);
     },
 };
 
diff --git a/package.json b/package.json
index 5a8d35efbb..f5bfc9602e 100644
--- a/package.json
+++ b/package.json
@@ -21,7 +21,7 @@
   "dependencies": {
     "@azure/storage-blob": "^12.28.0",
     "@hapi/joi": "^17.1.1",
-    "arsenal": "git+https://github.com/scality/Arsenal#8.2.35",
+    "arsenal": "git+https://github.com/scality/Arsenal#8.2.37",
     "async": "2.6.4",
     "aws-sdk": "^2.1692.0",
     "bucketclient": "scality/bucketclient#8.2.7",
diff --git a/tests/functional/aws-node-sdk/test/object/copyPart.js b/tests/functional/aws-node-sdk/test/object/copyPart.js
index f87780b706..87f8f6b0c9 100644
--- a/tests/functional/aws-node-sdk/test/object/copyPart.js
+++ b/tests/functional/aws-node-sdk/test/object/copyPart.js
@@ -582,85 +582,93 @@ describe('Object Part Copy', () => {
 
             it('should not corrupt object if overwriting an existing part by copying a part ' +
             'while the MPU is being completed', async () => {
-                    const finalObjETag = '"db77ebbae9e9f5a244a26b86193ad818-1"';
-                    process.stdout.write('Putting first part in MPU test"');
-                    const randomDestObjName = `copycatobject${Math.floor(Math.random() * 100000)}`;
+                const finalObjETag = '"db77ebbae9e9f5a244a26b86193ad818-1"';
+                process.stdout.write('Putting first part in MPU test"');
+                const randomDestObjName = `copycatobject${Math.floor(Math.random() * 100000)}`;
 
-                    const initiateRes = await s3
-                      .createMultipartUpload({
+                const initiateRes = await s3
+                    .createMultipartUpload({
                         Bucket: destBucketName,
                         Key: randomDestObjName,
-                      })
-                      .promise();
-                    const uploadId = initiateRes.UploadId;
+                    })
+                    .promise();
+                const uploadId = initiateRes.UploadId;
 
-                    const res = await s3
-                      .uploadPartCopy({
+                const res = await s3
+                    .uploadPartCopy({
                         Bucket: destBucketName,
                         Key: randomDestObjName,
                         CopySource: `${sourceBucketName}/${sourceObjName}`,
                         PartNumber: 1,
                         UploadId: uploadId,
-                      })
-                      .promise();
-                    assert.strictEqual(res.ETag, etag);
-                    assert(res.LastModified);
+                    })
+                    .promise();
+                assert.strictEqual(res.ETag, etag);
+                assert(res.LastModified);
+
+                process.stdout.write(
+            'Overwriting first part in MPU test and completing MPU at the same time',
+                );
 
-                    process.stdout.write(
-                      'Overwriting first part in MPU test and completing MPU at the same time',
-                    );
-                    const [completeRes, uploadRes] = await Promise.all([
-                      s3
+                const [completeRes, uploadRes] = await Promise.all([
+                    s3
                         .completeMultipartUpload({
-                          Bucket: destBucketName,
-                          Key: randomDestObjName,
-                          UploadId: uploadId,
-                          MultipartUpload: {
+                            Bucket: destBucketName,
+                            Key: randomDestObjName,
+                            UploadId: uploadId,
+                            MultipartUpload: {
                             Parts: [{ ETag: etag, PartNumber: 1 }],
-                          },
-                        })
-                        .promise()
-                        .catch(err => {
-                          throw err;
+                            },
+                        }).promise()
+                        .catch(async err => {
+                            const raceConditionOccurred = err?.code === 'InternalError'
+                                && err?.message === 'conflict deleting MPU parts metadata';
+
+                            if (raceConditionOccurred) {
+                                return Promise.resolve(null);
+                            }
+
+                            throw err;
                         }),
-                      s3
+                    s3
                         .uploadPartCopy({
-                          Bucket: destBucketName,
-                          Key: randomDestObjName,
-                          CopySource: `${sourceBucketName}/${sourceObjName}`,
-                          PartNumber: 1,
-                          UploadId: uploadId,
+                            Bucket: destBucketName,
+                            Key: randomDestObjName,
+                            CopySource: `${sourceBucketName}/${sourceObjName}`,
+                            PartNumber: 1,
+                            UploadId: uploadId,
                         })
                         .promise()
                         .catch(err => {
-                          const completeMPUFinishedEarlier =
-                            err && err.code === 'NoSuchKey';
-                          if (completeMPUFinishedEarlier) {
-                            return Promise.resolve(null);
-                          }
+                            const completeMPUFinishedEarlier = err && err.code === 'NoSuchKey';
+                            if (completeMPUFinishedEarlier) {
+                                return Promise.resolve(null);
+                            }
 
-                          throw err;
+                            throw err;
                         }),
-                    ]);
+                    ],
+                );
 
-                    if (uploadRes !== null) {
-                      assert.strictEqual(uploadRes.ETag, etag);
-                      assert(uploadRes.LastModified);
-                    }
+                if (uploadRes !== null) {
+                    assert.strictEqual(uploadRes.ETag, etag);
+                    assert(uploadRes.LastModified);
+                }
 
+                if (completeRes !== null) {
                     assert.strictEqual(completeRes.Bucket, destBucketName);
                     assert.strictEqual(completeRes.Key, randomDestObjName);
                     assert.strictEqual(completeRes.ETag, finalObjETag);
-                    process.stdout.write(
-                      'Getting object put by MPU with ' + 'overwrite part',
-                    );
-                    const resGet = await s3
-                      .getObject({
+                }
+
+                process.stdout.write('Getting object put by MPU with overwrite part');
+                const resGet = await s3
+                    .getObject({
                         Bucket: destBucketName,
                         Key: randomDestObjName,
-                      })
-                      .promise();
-                    assert.strictEqual(resGet.ETag, finalObjETag);
+                    })
+                    .promise();
+                assert.strictEqual(resGet.ETag, finalObjETag);
             });
         });
 
diff --git a/yarn.lock b/yarn.lock
index 9edededc50..e1b4a475a6 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -1451,9 +1451,9 @@ arraybuffer.prototype.slice@^1.0.4:
   optionalDependencies:
     ioctl "^2.0.2"
 
-"arsenal@git+https://github.com/scality/Arsenal#8.2.35":
-  version "8.2.35"
-  resolved "git+https://github.com/scality/Arsenal#51640ec484e521925e2d3a8b7ce5912f61590b8d"
+"arsenal@git+https://github.com/scality/Arsenal#8.2.37":
+  version "8.2.37"
+  resolved "git+https://github.com/scality/Arsenal#a000b510e641b819f86d91371f638f1cbc57144f"
   dependencies:
     "@azure/identity" "^4.13.0"
     "@azure/storage-blob" "^12.28.0"