diff --git a/common/src/util/freebuff-streak.ts b/common/src/util/freebuff-streak.ts
index f61f22832a..4b70bc2e97 100644
--- a/common/src/util/freebuff-streak.ts
+++ b/common/src/util/freebuff-streak.ts
@@ -48,7 +48,7 @@ export function getFreebuffUsageDateKey(
 
 export function addDaysToDateKey(dateKey: string, days: number): string {
   const date = new Date(`${dateKey}T00:00:00.000Z`)
-  if (Number.isNaN(date.getTime())) {
+  if (!Number.isFinite(date.getTime())) {
     throw new Error(`Invalid date key: ${dateKey}`)
   }