diff --git a/changelog.d/14347.bugfix b/changelog.d/14347.bugfix
new file mode 100644
index 0000000000000000000000000000000000000000..91975757aedbe3c76470d748dc979307ef94b85c
--- /dev/null
+++ b/changelog.d/14347.bugfix
@@ -0,0 +1 @@
+Fix a bug introduced in Synapse 1.64.0rc1 which could cause log spam when fetching events from other homeservers.
diff --git a/synapse/federation/federation_client.py b/synapse/federation/federation_client.py
index fa225182be0d2d82ed8497bb986d70b68fcc22bb..c4c0bc7315b4519179c6d5d16f2c1ce8a8e3747b 100644
--- a/synapse/federation/federation_client.py
+++ b/synapse/federation/federation_client.py
@@ -465,7 +465,7 @@ class FederationClient(FederationBase):
                     pdu_attempts[destination] = now
 
                     logger.info(
-                        "get_pdu(event_id=): Failed to get PDU from %s because %s",
+                        "get_pdu(event_id=%s): Failed to get PDU from %s because %s",
                         event_id,
                         destination,
                         e,