Why does a player who joins mid-game miss state set before they joined?

MultiplayerSynchronizer's Spawn flag controls what's replicated to a peer at spawn time. If a property only has Sync (continuous) but not Spawn (initial), late joiners get the spawn but not the historical state.

How do I set initial state for late joiners?

Tick Spawn for every property the server sets pre-spawn (health, score, inventory). Or send a custom 'world snapshot' RPC to the new peer immediately after their connection succeeds.

What about signal-driven events that fired before joining?

Signals don't replay. Track the resulting state in a replicated property and send via Spawn, or send a snapshot RPC with the cumulative event log.

Fix: Godot 4 Multiplayer Late Joiner Sees Wrong Initial State

Quick answer: Tick Spawn on every replicated property in MultiplayerSynchronizer’s Replication Config. For event-driven state that pre-dates the join, send a custom snapshot RPC right after the peer connects.

Player joins midway. Their HUD shows everyone’s score as 0. Server has the actual scores; the synchronizer didn’t send them at spawn.

The Symptom

Late-joining peers see default values for properties that should reflect server state. Continuous changes after join replicate fine; pre-join state never arrives.

The Fix

MultiplayerSynchronizer:
  Replication Config:
    .score        Sync: true    Spawn: true
    .health       Sync: true    Spawn: true
    .team_id      Sync: false   Spawn: true   # once at spawn, never updates

Spawn = true makes the property included in the spawn payload. Late joiners receive the value as part of the spawn replication.

Custom Snapshot RPC

# On the server
func _on_peer_connected(id: int) -> void:
    var snapshot := {
        "scores": scores,
        "round": current_round,
        "timer": round_timer,
    }
    rpc_id(id, "_receive_snapshot", snapshot)

@rpc("authority", "reliable")
func _receive_snapshot(snapshot: Dictionary) -> void:
    # Apply on the client
    scores = snapshot["scores"]
    ...

Reliable RPC ensures the new peer gets the snapshot exactly once. Apply on the client before showing the game.

Verifying

Start a game, advance state, connect a second peer. Late joiner should see the current state, not defaults. Test with various Spawn flag combinations.

“Spawn flag for state. Snapshot RPC for events. Late joiners catch up.”

Related Issues

For MultiplayerSynchronizer config, see synchronizer config. For MultiplayerSpawner, see spawner.

Spawn flag plus snapshot RPC. State arrives.