diff --git a/ortools/linear_solver/java/LinearSolverTest.java b/ortools/linear_solver/java/LinearSolverTest.java
index d1afd0683d8..92bd14201be 100644
--- a/ortools/linear_solver/java/LinearSolverTest.java
+++ b/ortools/linear_solver/java/LinearSolverTest.java
@@ -53,8 +53,6 @@ private void runBasicCtor(MPSolver.OptimizationProblemType solverType) {
   @Test
   public void testMPSolver_basicCtor() {
     runBasicCtor(MPSolver.OptimizationProblemType.GLOP_LINEAR_PROGRAMMING);
-    runBasicCtor(MPSolver.OptimizationProblemType.GLPK_LINEAR_PROGRAMMING);
-    runBasicCtor(MPSolver.OptimizationProblemType.GLPK_MIXED_INTEGER_PROGRAMMING);
     runBasicCtor(MPSolver.OptimizationProblemType.CLP_LINEAR_PROGRAMMING);
     runBasicCtor(MPSolver.OptimizationProblemType.CBC_MIXED_INTEGER_PROGRAMMING);
   }
@@ -129,10 +127,12 @@ private void runLinearSolver(
   public void testMPSolver_linearSolver() {
     runLinearSolver(MPSolver.OptimizationProblemType.GLOP_LINEAR_PROGRAMMING, false);
     runLinearSolver(MPSolver.OptimizationProblemType.CLP_LINEAR_PROGRAMMING, false);
-    runLinearSolver(MPSolver.OptimizationProblemType.GLPK_LINEAR_PROGRAMMING, false);
+    // TODO(b/312134897): Uncomment this.
+    // runLinearSolver(MPSolver.OptimizationProblemType.GLPK_LINEAR_PROGRAMMING, false);
 
     runLinearSolver(MPSolver.OptimizationProblemType.CBC_MIXED_INTEGER_PROGRAMMING, true);
-    runLinearSolver(MPSolver.OptimizationProblemType.GLPK_MIXED_INTEGER_PROGRAMMING, true);
+    // TODO(b/312134897): Uncomment this.
+    // runLinearSolver(MPSolver.OptimizationProblemType.GLPK_MIXED_INTEGER_PROGRAMMING, true);
     runLinearSolver(MPSolver.OptimizationProblemType.SCIP_MIXED_INTEGER_PROGRAMMING, true);
   }
 
@@ -224,7 +224,8 @@ private void runFirstLinearExample(MPSolver.OptimizationProblemType problemType)
   public void testMPSolver_firstLinearExample() {
     runFirstLinearExample(MPSolver.OptimizationProblemType.GLOP_LINEAR_PROGRAMMING);
     runFirstLinearExample(MPSolver.OptimizationProblemType.CLP_LINEAR_PROGRAMMING);
-    runFirstLinearExample(MPSolver.OptimizationProblemType.GLPK_LINEAR_PROGRAMMING);
+    // TODO(b/312134897): Uncomment this.
+    // runFirstLinearExample(MPSolver.OptimizationProblemType.GLPK_LINEAR_PROGRAMMING);
     runFirstLinearExample(MPSolver.OptimizationProblemType.GUROBI_LINEAR_PROGRAMMING);
   }
 
@@ -266,7 +267,8 @@ private void runFirstMIPExample(MPSolver.OptimizationProblemType problemType) {
   public void testMPSolver_firstMIPExample() {
     runFirstMIPExample(MPSolver.OptimizationProblemType.BOP_INTEGER_PROGRAMMING);
     runFirstMIPExample(MPSolver.OptimizationProblemType.CBC_MIXED_INTEGER_PROGRAMMING);
-    runFirstMIPExample(MPSolver.OptimizationProblemType.GLPK_MIXED_INTEGER_PROGRAMMING);
+    // TODO(b/312134897): Uncomment this.
+    // runFirstMIPExample(MPSolver.OptimizationProblemType.GLPK_MIXED_INTEGER_PROGRAMMING);
     runFirstMIPExample(MPSolver.OptimizationProblemType.SCIP_MIXED_INTEGER_PROGRAMMING);
     runFirstMIPExample(MPSolver.OptimizationProblemType.SAT_INTEGER_PROGRAMMING);
     runFirstMIPExample(MPSolver.OptimizationProblemType.GUROBI_MIXED_INTEGER_PROGRAMMING);
@@ -318,11 +320,13 @@ private void runSuccessiveObjectives(MPSolver.OptimizationProblemType problemTyp
   public void testMPSolver_successiveObjectives() {
     runSuccessiveObjectives(MPSolver.OptimizationProblemType.GLOP_LINEAR_PROGRAMMING);
     runSuccessiveObjectives(MPSolver.OptimizationProblemType.CLP_LINEAR_PROGRAMMING);
-    runSuccessiveObjectives(MPSolver.OptimizationProblemType.GLPK_LINEAR_PROGRAMMING);
+    // TODO(b/312134897): Uncomment this.
+    // runSuccessiveObjectives(MPSolver.OptimizationProblemType.GLPK_LINEAR_PROGRAMMING);
     runSuccessiveObjectives(MPSolver.OptimizationProblemType.GUROBI_LINEAR_PROGRAMMING);
 
     runSuccessiveObjectives(MPSolver.OptimizationProblemType.CBC_MIXED_INTEGER_PROGRAMMING);
-    runSuccessiveObjectives(MPSolver.OptimizationProblemType.GLPK_MIXED_INTEGER_PROGRAMMING);
+    // TODO(b/312134897): Uncomment this.
+    // runSuccessiveObjectives(MPSolver.OptimizationProblemType.GLPK_MIXED_INTEGER_PROGRAMMING);
     runSuccessiveObjectives(MPSolver.OptimizationProblemType.SCIP_MIXED_INTEGER_PROGRAMMING);
     runSuccessiveObjectives(MPSolver.OptimizationProblemType.SAT_INTEGER_PROGRAMMING);
     runSuccessiveObjectives(MPSolver.OptimizationProblemType.GUROBI_MIXED_INTEGER_PROGRAMMING);
@@ -375,11 +379,13 @@ private void runObjectiveOffset(MPSolver.OptimizationProblemType problemType) {
   public void testMPSolver_objectiveOffset() {
     runObjectiveOffset(MPSolver.OptimizationProblemType.GLOP_LINEAR_PROGRAMMING);
     runObjectiveOffset(MPSolver.OptimizationProblemType.CLP_LINEAR_PROGRAMMING);
-    runObjectiveOffset(MPSolver.OptimizationProblemType.GLPK_LINEAR_PROGRAMMING);
+    // TODO(b/312134897): Uncomment this.
+    // runObjectiveOffset(MPSolver.OptimizationProblemType.GLPK_LINEAR_PROGRAMMING);
     runObjectiveOffset(MPSolver.OptimizationProblemType.GUROBI_LINEAR_PROGRAMMING);
 
     runObjectiveOffset(MPSolver.OptimizationProblemType.CBC_MIXED_INTEGER_PROGRAMMING);
-    runObjectiveOffset(MPSolver.OptimizationProblemType.GLPK_MIXED_INTEGER_PROGRAMMING);
+    // TODO(b/312134897): Uncomment this.
+    // runObjectiveOffset(MPSolver.OptimizationProblemType.GLPK_MIXED_INTEGER_PROGRAMMING);
     runObjectiveOffset(MPSolver.OptimizationProblemType.SCIP_MIXED_INTEGER_PROGRAMMING);
     runObjectiveOffset(MPSolver.OptimizationProblemType.SAT_INTEGER_PROGRAMMING);
     runObjectiveOffset(MPSolver.OptimizationProblemType.GUROBI_MIXED_INTEGER_PROGRAMMING);
diff --git a/ortools/linear_solver/python/py.typed b/ortools/linear_solver/python/py.typed
new file mode 100644
index 00000000000..e69de29bb2d
diff --git a/ortools/pdlp/primal_dual_hybrid_gradient.cc b/ortools/pdlp/primal_dual_hybrid_gradient.cc
index b872aebfd15..4f28078531d 100644
--- a/ortools/pdlp/primal_dual_hybrid_gradient.cc
+++ b/ortools/pdlp/primal_dual_hybrid_gradient.cc
@@ -1459,7 +1459,9 @@ PreprocessSolver::UpdateIterationStatsAndCheckTermination(
                      POINT_TYPE_AVERAGE_ITERATE, last_primal_start_point,
                      last_dual_start_point, stats);
   }
-  if (working_primal_delta != nullptr && working_dual_delta != nullptr) {
+  // Undoing presolve doesn't work for iterate differences.
+  if (!presolve_info_.has_value() && working_primal_delta != nullptr &&
+      working_dual_delta != nullptr) {
     ComputeConvergenceAndInfeasibilityFromWorkingSolution(
         params, *working_primal_delta, *working_dual_delta,
         POINT_TYPE_ITERATE_DIFFERENCE, nullptr,
@@ -1531,6 +1533,9 @@ void PreprocessSolver::ComputeConvergenceAndInfeasibilityFromWorkingSolution(
       EpsilonRatio(criteria.eps_optimal_dual_residual_absolute(),
                    criteria.eps_optimal_dual_residual_relative());
   if (presolve_info_.has_value()) {
+    // Undoing presolve doesn't make sense for iterate differences.
+    CHECK_NE(candidate_type, POINT_TYPE_ITERATE_DIFFERENCE);
+
     PrimalAndDualSolution original = RecoverOriginalSolution(
         {.primal_solution = working_primal, .dual_solution = working_dual});
     if (convergence_information != nullptr) {
diff --git a/ortools/pdlp/primal_dual_hybrid_gradient_test.cc b/ortools/pdlp/primal_dual_hybrid_gradient_test.cc
index 4e827e0a9be..2e949cf457d 100644
--- a/ortools/pdlp/primal_dual_hybrid_gradient_test.cc
+++ b/ortools/pdlp/primal_dual_hybrid_gradient_test.cc
@@ -1610,6 +1610,39 @@ TEST(PrimalDualHybridGradientTest, DetailedTerminationCriteria) {
               EigenArrayNear<double>({0.0, 1.5, -3.5, 0.0}, 1.0e-4));
 }
 
+// Regression test for b/311455838. Note that this test only fails in debug
+// mode, when an infeasible primal variable (from the iterate differences)
+// violates presolve's assumptions and triggers a DCHECK() failure.
+TEST(PrimalDualHybridGradientTest, IterateDifferenceBoundsInPresolve) {
+  // A trivial (but very badly scaled) LP found by fuzzing.
+  QuadraticProgram lp(2, 1);
+  lp.objective_offset = -3.0e+23;
+  lp.objective_vector =
+      VectorXd{{2.7369110631344083e-48, -3.0517578125211636e-05}};
+  lp.constraint_lower_bounds = VectorXd{{-2.7369110631344083e-48}};
+  lp.constraint_upper_bounds = VectorXd{{0}};
+  lp.variable_lower_bounds = VectorXd{{1.8446744073709552e+21, -1.0}};
+  lp.variable_upper_bounds = VectorXd{{kInfinity, 1.8446744073709552e+21}};
+  lp.constraint_matrix.coeffRef(0, 0) = -2.7369110631344083e-48;
+  lp.constraint_matrix.coeffRef(0, 1) = 1.0;
+  lp.constraint_matrix.makeCompressed();
+
+  PrimalDualHybridGradientParams params;
+  params.mutable_termination_criteria()->set_iteration_limit(40);
+  auto& presolve_options = *params.mutable_presolve_options();
+  presolve_options.set_use_glop(true);
+  presolve_options.mutable_glop_parameters()->set_solve_dual_problem(
+      operations_research::glop::GlopParameters::LET_SOLVER_DECIDE);
+  presolve_options.mutable_glop_parameters()->set_dualizer_threshold(
+      1.3574141825331e-312);
+  params.set_infinite_constraint_bound_threshold(1.34785525461908e-312);
+
+  SolverResult output = PrimalDualHybridGradient(lp, params);
+  EXPECT_THAT(
+      output.solve_log.termination_reason(),
+      AnyOf(TERMINATION_REASON_ITERATION_LIMIT, TERMINATION_REASON_OPTIMAL));
+}
+
 // `FeasibilityPolishingTest` sets `params_` for feasibility polishing, and to
 // avoid PDLP features that disrupt a simple analysis of the performance with
 // and without feasibility polishing (primal weight adjustments, dynamic step
diff --git a/ortools/sat/python/py.typed b/ortools/sat/python/py.typed
new file mode 100644
index 00000000000..e69de29bb2d