Quick answer: Godot 4 MultiplayerSynchronizer dropping replicated properties after renaming the synced node? Config stores property paths; renames break them - re-add via inspector.

Renamed a child node from Sprite2D to PlayerSprite. SceneReplicationConfig now lists the old path; sync silently fails.

Re-add via inspector

Open the SceneReplicationConfig resource. Remove the old path; add the new one. Drag-drop is safer than typing.

Or rename in code

config.add_property(NodePath("PlayerSprite:position"))

Programmatic add ensures the path is current.

Validate at load

On scene load, iterate the config's paths and verify each resolves. Log mismatches; fix at edit time.

“Replication paths are strings. String renames don't refactor.”

Avoid renaming synced nodes after replication is set up. If you must, run a verify pass; the failure is silent at runtime.