Quick answer: Godot 4 MultiplayerSynchronizer throwing 'property not found' at runtime? Replication config holds stale paths after a child node was removed - clean up the config.
Removed a child node. The MultiplayerSynchronizer's replication config still references it; runtime error.
Edit the config in inspector
Open the SceneReplicationConfig. Remove the orphan path entry. Save.
Or rebuild from scratch
For complex configs, delete and re-add. Less error-prone than surgical edits.
Validate at startup
for path in config.get_properties():
assert get_node_or_null(path)Custom validation script. Catches stale paths before runtime.
“Replication configs are static references. Static references rot when scenes change.”
After scene restructures, validate every replication config. Build a tool that auto-detects orphans; refactor stays safe.