diff --git a/changelog.d/15309.bugfix b/changelog.d/15309.bugfix
new file mode 100644
index 0000000000..4d3fe4e4b1
--- /dev/null
+++ b/changelog.d/15309.bugfix
@@ -0,0 +1 @@
+Fix a bug introduced in Synapse 1.76.0 where responses from worker deployments could include an internal `_INT_STREAM_POS` key.
diff --git a/synapse/replication/http/_base.py b/synapse/replication/http/_base.py
index c20d9c7e9d..8c2c54c07a 100644
--- a/synapse/replication/http/_base.py
+++ b/synapse/replication/http/_base.py
@@ -345,7 +345,7 @@ class ReplicationEndpoint(metaclass=abc.ABCMeta):
                 _outgoing_request_counter.labels(cls.NAME, 200).inc()
 
                 # Wait on any streams that the remote may have written to.
-                for stream_name, position in result.get(
+                for stream_name, position in result.pop(
                     _STREAM_POSITION_KEY, {}
                 ).items():
                     await replication.wait_for_stream_position(