### Godot version

4.1.dev4

### System information

Windows 10 - Godot 4.1.dev4 - Compatibility

### Issue description

When you syncronize 2 variables and both are in watched mode (taking out the "sync" property too) the server crashes

### Steps to reproduce

Create a MultiplayerSynchronizer, export 2 variables from a script, connect the server and the client and the server will crash instantly

In the project I give, the server and client are connected automatically when you use 2 debug instances when pressing play

### Minimal reproduction project

[minimalproject.zip](https://github.com/godotengine/godot/files/11665652/minimalproject.zip)

ofs += size;
		sync->emit_signal(SNAME("delta_synchronized"));
#ifdef DEBUG_ENABLED
		_profile_node_data("delta_in", sync->get_instance_id(), size);
#endif
	}
	return OK;
}
void SceneReplicationInterface::_send_sync(int p_peer, const HashSet<ObjectID> p_synchronizers, uint16_t p_sync_net_time, uint64_t p_usec) {
	MAKE_ROOM( 3 +  4 + 4 + sync_mtu);
	uint8_t *ptr = packet_cache.ptrw();
	ptr[0] = SceneMultiplayer::NETWORK_COMMAND_SYNC;
	int ofs = 1;
	ofs += encode_uint16(p_sync_net_time, &ptr[1]);
	
	
	for (const ObjectID &oid : p_synchronizers) {
		MultiplayerSynchronizer *sync = get_id_as<MultiplayerSynchronizer>(oid);
		ERR_CONTINUE(!sync || !sync->get_replication_config().is_valid() || !sync->is_multiplayer_authority());
		if (!sync->update_outbound_sync_time(p_usec)) {
			continue; 
		}
		Node *node = sync->get_root_node();
		ERR_CONTINUE(!node);
		uint32_t net_id = sync->get_net_id();
		if (!_verify_synchronizer(p_peer, sync, net_id)) {
			
			continue;
		}
		int size;