[CI][PD] Skip the flaky decode HiCache file-backend disaggregation test (#39368)

test/registered/disaggregation/test_disaggregation_decode_radix_cache.py

@@ -49,7 +49,9 @@ class DisaggregationDecodeRadixCacheTestMixin:
     extra_decode_args = ["--disaggregation-decode-enable-radix-cache"]
     transfer_backend_name = None
     model_name = DEFAULT_MODEL_NAME_FOR_TEST
-    gsm8k_min_score = 0.80
+    # Observed range on Llama-3.1-8B over 500 gsm8k examples is 0.798-0.818,
+    # so a 0.80 bar rejects a healthy run; matches test_disaggregation_basic.py.
+    gsm8k_min_score = 0.74
 
     @classmethod
     def setUpClass(cls):
@@ -152,6 +154,10 @@ class TestDisaggregationDecodeRadixCacheMooncake(
     transfer_backend_name = "mooncake"
 
 
+# Workaround for #39367: the decode worker intermittently never leaves
+# KVPoll.Bootstrapping on the first request, so prefill times out after 300s and
+# the file burns its whole 1200s budget; drop the skip once that issue is fixed.
+@unittest.skip("temporarily disabled: flaky PD bootstrap hang, see #39367")
 @unittest.skipUnless(
     is_in_ci() or _has_mooncake(),
     "Mooncake is required for decode radix cache disaggregation coverage.",