fix(flags): keep dropped flag exposures out of the dedupe cache

Only mark a $feature_flag_called event as reported when capture() returns
an event UUID. A should_capture rejection no longer suppresses the same
exposure from a later allowed context on the shared client.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Generated-By: PostHog Desktop
Task-Id: bdf93d58-c0c1-4a15-a1e6-78b6a3944b02

Author: posthog[bot]

posthog/client.py

@@ -4231,15 +4231,17 @@ def _capture_feature_flag_called_if_needed(
                 _MINIMAL_FLAG_CALLED_EVENT_PROPERTIES
             )
 
-        self.capture(
+        event_uuid = self.capture(
             "$feature_flag_called",
             distinct_id=distinct_id,
             properties=properties,
             groups=groups or {},
             disable_geoip=disable_geoip,
             **extra_capture_kwargs,
         )
-        reported_flags.add(feature_flag_reported_key)
+        # A dropped event was not reported, so a later allowed call must still send it.
+        if event_uuid is not None:
+            reported_flags.add(feature_flag_reported_key)
 
     def get_remote_config_payload(self, key: str):
         """

posthog/test/test_should_capture.py

@@ -112,6 +112,54 @@ def capture_in_context(private):
     assert client.disabled is False
 
 
+@pytest.mark.parametrize(
+    "access_flag",
+    [
+        lambda client: client.get_feature_flag_result(
+            "beta-feature", "user1", only_evaluate_locally=True
+        ),
+        lambda client: client.evaluate_flags(
+            "user1", only_evaluate_locally=True
+        ).is_enabled("beta-feature"),
+    ],
+    ids=["get_feature_flag_result", "evaluate_flags"],
+)
+def test_rejected_flag_exposure_is_still_sent_from_an_allowed_context(access_flag):
+    private_context = ContextVar("private_context", default=False)
+    sent_events = []
+
+    def before_send(event):
+        sent_events.append(event["event"])
+        return event
+
+    client = Client(
+        FAKE_TEST_API_KEY,
+        secret_key="test",
+        should_capture=lambda: not private_context.get(),
+        before_send=before_send,
+        send=False,
+    )
+    client.feature_flags = [
+        {
+            "id": 1,
+            "key": "beta-feature",
+            "active": True,
+            "filters": {"groups": [{"properties": [], "rollout_percentage": 100}]},
+        }
+    ]
+
+    token = private_context.set(True)
+    try:
+        access_flag(client)
+    finally:
+        private_context.reset(token)
+    assert sent_events == []
+
+    access_flag(client)
+    access_flag(client)
+    assert sent_events == ["$feature_flag_called"]
+
+
 def test_filter_survives_client_reinitialization_after_fork():
     should_capture = mock.Mock(return_value=False)
     client = Client(FAKE_TEST_API_KEY, should_capture=should_capture, send=False)