diff --git a/contributing/samples/gepa/experiment.py b/contributing/samples/gepa/experiment.py
index 2f5d03a772..f68b349d9c 100644
--- a/contributing/samples/gepa/experiment.py
+++ b/contributing/samples/gepa/experiment.py
@@ -43,7 +43,6 @@
 from tau_bench.types import EnvRunResult
 from tau_bench.types import RunConfig
 import tau_bench_agent as tau_bench_agent_lib
-
 import utils
 
 
diff --git a/contributing/samples/gepa/run_experiment.py b/contributing/samples/gepa/run_experiment.py
index cfd850b3a3..1bc4ee58c8 100644
--- a/contributing/samples/gepa/run_experiment.py
+++ b/contributing/samples/gepa/run_experiment.py
@@ -25,7 +25,6 @@
 from absl import flags
 import experiment
 from google.genai import types
-
 import utils
 
 _OUTPUT_DIR = flags.DEFINE_string(
diff --git a/src/google/adk/runners.py b/src/google/adk/runners.py
index 4cf5a29546..e6b6c2a51b 100644
--- a/src/google/adk/runners.py
+++ b/src/google/adk/runners.py
@@ -1208,6 +1208,7 @@ async def _setup_context_for_resumed_invocation(
       ValueError: If the session has no events to resume; If no user message is
         available for resuming the invocation; Or if the app is not resumable.
     """
+
     if not session.events:
       raise ValueError(f'Session {session.id} has no events to resume.')
 
@@ -1215,6 +1216,22 @@ async def _setup_context_for_resumed_invocation(
     user_message = new_message or self._find_user_message_for_invocation(
         session.events, invocation_id
     )
+
+    # === [START FIX] Fallback mechanism ===
+    if not user_message and session.events:
+      # If exact invocation match failed, try to find the latest user message
+      # This handles cases where invocation IDs might have drifted or for generic resume
+      for event in reversed(session.events):
+        if event.author == 'user' and event.content:
+          logger.warning(
+              'Could not find user message for invocation %s. Falling back to '
+              'the latest user message in the session.',
+              invocation_id,
+          )
+          user_message = event.content
+          break
+    # === [END FIX] ===
+
     if not user_message:
       raise ValueError(
           f'No user message available for resuming invocation: {invocation_id}'