better config sync without suppressing

backend/src/utilities/bridge_link_state_manager.py

@@ -246,6 +246,13 @@ class BridgeLinkStateWatcher:
         )
 
         if failing_members:
+            config_source = self._find_config_sync_source(states, preferred_ifname=source_ifname)
+            if config_source is not None and self._has_config_mismatch(config_source, states):
+                with self._lock:
+                    self._failing_since = {}
+                self._sync_member_configuration(config_source, states)
+                return
+
             matured_failing_members = self._track_failing_members(failing_members, now)
             if not matured_failing_members:
                 self._set_last_action(
@@ -311,6 +318,39 @@ class BridgeLinkStateWatcher:
         state = states.get(ifname)
         return state is not None and state.link_ready
 
+    def _find_config_sync_source(
+        self,
+        states: dict[str, MemberLinkState],
+        preferred_ifname: Optional[str] = None,
+    ) -> Optional[str]:
+        """Pick a healthy member whose configuration should be mirrored to siblings."""
+        candidates: list[str] = []
+        if preferred_ifname:
+            candidates.append(preferred_ifname)
+        candidates.extend(ifname for ifname in sorted(states) if ifname != preferred_ifname)
+
+        for ifname in candidates:
+            if self._is_source_eligible(ifname, states):
+                return ifname
+
+        return None
+
+    def _has_config_mismatch(self, source_ifname: str, states: dict[str, MemberLinkState]) -> bool:
+        """Return whether any sibling differs from the chosen source configuration."""
+        source = states.get(source_ifname)
+        if source is None:
+            return False
+
+        for target_ifname, target in states.items():
+            if target_ifname == source_ifname:
+                continue
+            if source.mtu is not None and target.mtu is not None and source.mtu != target.mtu:
+                return True
+            if source.ethernet_profile is not None and target.ethernet_profile is not None and source.ethernet_profile != target.ethernet_profile:
+                return True
+
+        return False
+
     def _track_failing_members(self, failing_members: list[str], now: float) -> list[str]:
         """Record first-seen timestamps and return failures that exceeded the holdoff."""
         with self._lock: