You’ve probably never seen a real answer to this, because it really depends on how you’ve setup everything ( menus, characters, levels etc ).
Two of the crucial differences between editor mode and standalone ( packaged ), are
-
The order of initialization is not the same
-
The timing of operations is not the same
Basically, what it comes down to, is that you can’t assume object A will be ready when you start object B. You have to code things so that A will assume B is not ready and have some sort of strategy for coping with that.
Many people will put a delay on begin play in a critical blueprint. In your case, you could try that. I assume you are spawning the chosen character and possessing? So you could have a delay between spawning and possessing, maybe.
Of course, in the end, delay is not the answer, because things will be very different on a hot machine compared to a ‘potato’ 