fix(bb): skip BatchMergeTests.TooManySubtablesFails under _GLIBCXX_DEBUG

barretenberg/cpp/src/barretenberg/goblin/batch_merge.test.cpp

@@ -471,6 +471,17 @@ TYPED_TEST(BatchMergeTests, TooManySubtablesFails)
         GTEST_SKIP() << "This test in native setting fails due to a deserialization failure. The verifier path in the "
                         "same for native and recursive code, so it's enough to test the recursive code.";
     } else {
+#ifndef NDEBUG
+        // BB_DISABLE_ASSERTS lets the prover continue past the N <= max_subtables BB_ASSERT_LTE in
+        // BatchMergeProver::construct_proof. Once past it, compute_degree_check_polynomial reads
+        // degree_check_challenges[idx] for idx up to flattened_columns.size() - 1, which exceeds
+        // the (max_subtables + 1) * NUM_WIRES challenges allocated. In release this is silent UB
+        // and the verifier still rejects the malformed proof; under _GLIBCXX_DEBUG the bounds
+        // check on std::vector::operator[] aborts the prover before the verifier runs. The
+        // verifier-rejection contract here is exercised by the release build.
+        GTEST_SKIP() << "Skipped under _GLIBCXX_DEBUG: BB_DISABLE_ASSERTS bypasses the prover's N <= max_subtables "
+                        "guard, and the bounds-checked vector access then aborts before the verifier can reject.";
+#else
         BB_DISABLE_ASSERTS();
         auto op_queue = make_op_queue_with_n_subtables(TestFixture::NumSubtables + 1);
         auto res = TestFixture::prove_and_verify(op_queue);
@@ -479,6 +490,7 @@ TYPED_TEST(BatchMergeTests, TooManySubtablesFails)
         if constexpr (TestFixture::IsRecursive) {
             EXPECT_FALSE(res.circuit_ok); // Assertions fail
         }
+#endif
     }
 }