diff --git a/tensorrt_llm/executor/proxy.py b/tensorrt_llm/executor/proxy.py
index 5a446fc4811e..92782c5ca614 100644
--- a/tensorrt_llm/executor/proxy.py
+++ b/tensorrt_llm/executor/proxy.py
@@ -675,12 +675,11 @@ def _register_worker_processes(self, status: tuple) -> None:
         """Register identities returned by locally spawned MPI workers.
 
         Test session reuse replaces this module's ``MpiPoolSession`` class
-        reference with a factory, so identify pool-backed sessions by excluding
-        the external communication session types.
+        reference with a factory, so use the polymorphic ``is_comm_session``
+        predicate rather than ``isinstance`` — the module-level symbol may be
+        rebound to a factory at runtime, breaking ``isinstance``.
         """
-        if not isinstance(
-                self.mpi_session,
-            (MpiCommSession, RemoteMpiCommSessionClient)) and len(status) == 3:
+        if not self.mpi_session.is_comm_session() and len(status) == 3:
             worker_process_identities: List[WorkerProcessIdentity] = status[2]
             self._worker_process_monitor.register(worker_process_identities)
 
diff --git a/tests/integration/test_lists/waives.txt b/tests/integration/test_lists/waives.txt
index fc8bae3f0f10..3510ef1144b1 100644
--- a/tests/integration/test_lists/waives.txt
+++ b/tests/integration/test_lists/waives.txt
@@ -19,7 +19,6 @@ accuracy/test_disaggregated_serving.py::TestQwen3_30B_A3B::test_mixed_ctx_gen_mo
 accuracy/test_llm_api_autodeploy.py::TestNemotronNanoV3::test_accuracy[nvfp4-4-attn_dp_off-trtllm] SKIP (https://nvbugs/6367792)
 accuracy/test_llm_api_autodeploy.py::TestNemotronSuperV3::test_mtp[nvfp4_ws8_80gb-trtllm] SKIP (https://nvbugs/6450341)
 accuracy/test_llm_api_autodeploy.py::TestQwen3_5_397B_MoE::test_bf16_small[4] SKIP (https://nvbugs/6507114)
-accuracy/test_llm_api_pytorch.py::TestDeepSeekR1::test_fp8_blockscale[throughput] SKIP (https://nvbugs/6561775)
 accuracy/test_llm_api_pytorch.py::TestDeepSeekR1::test_fp8_blockscale[throughput_mtp] SKIP (https://nvbugs/6428101)
 accuracy/test_llm_api_pytorch.py::TestDeepSeekR1::test_fp8_blockscale[throughput_mtp_trtllm] SKIP (https://nvbugs/6426868)
 accuracy/test_llm_api_pytorch.py::TestDeepSeekR1::test_nvfp4_multi_gpus[latency] SKIP (https://nvbugs/6561778)
@@ -232,7 +231,6 @@ full:H100/accuracy/test_disaggregated_serving.py::TestDeepSeekV3Lite::test_auto_
 full:H100/accuracy/test_llm_api_pytorch.py::TestDeepSeekV3Lite::test_bfloat16[mtp_nextn=2-attention_dp=True-cuda_graph=True-overlap_scheduler=True-torch_compile=True-enable_chunked_prefill=True-v2_kv_cache=False] SKIP (https://nvbugs/6422343)
 full:H100/accuracy/test_llm_api_pytorch.py::TestDeepSeekV3Lite::test_bfloat16[mtp_nextn=2-attention_dp=True-cuda_graph=True-overlap_scheduler=True-torch_compile=True-enable_chunked_prefill=True-v2_kv_cache=True] SKIP (https://nvbugs/6422343)
 full:H100/accuracy/test_llm_api_pytorch.py::TestGPTOSS::test_w4_1gpu[v2_kv_cache-True-True-cutlass-auto] SKIP (https://nvbugs/6529792)
-full:H100/accuracy/test_llm_api_pytorch.py::TestQwen3_30B_A3B_Instruct_2507::test_skip_softmax_attention_4gpus[target_sparsity_0.9-fp8kv=False] SKIP (https://nvbugs/6523809)
 full:H100/accuracy/test_llm_api_pytorch.py::TestQwen3_5_35B_A3B::test_bf16[tp1-CUTLASS] SKIP (https://nvbugs/6273850)
 full:H100/disaggregated/test_disaggregated.py::test_disaggregated_logprobs_serving[llama-3.1-8b-instruct] SKIP (https://nvbugs/6275959)
 full:H100/disaggregated/test_disaggregated.py::test_disaggregated_stress_test[input8k-output1k-conc512-qwen3_32b_fp8_stress] SKIP (https://nvbugs/6312828)