I am sorry to read you are running into randomly happening crashes. The stack trace shows how much deeper Unity goes into it's own Instantiate methods and for me, this indicates the issue is not directly caused by PUN but it certainly is caused by some race condition between instantiation and level loading. If the objects refer to some code in the scene, this may be related but essentially, I have no idea what the actual issue is. What I'd suggest: Update Unity. You use 2019.3.0f6 but there have been many many updates since. Better even: Those updates are for a LTS version and should only fix issues, so you have a lot to gain with low risk. Set IsMessageQueueRunning. You are spot on with the usage and implications. It will pause dispatching of incoming messages. Instantiation will be delayed until after the scene is loaded, which should be good in any case. The Master Client not running into this issue might be due to loading the scene first, then instantiating the networked objects.