Standalone packaged build problems. Common troubleshooting tips?

My game runs fine in the editor but ceases to work correctly in a standalone packaged project. I have fixed some of these in the past from setting a reference to an object that was supposed to be destroyed to null. But then got into some more problems with the packaged build.

What are the problems that are common in a packaged build? Any good troubleshooting tips for a packaged build?

I was thinking it was a sequence of events problem, or the data is placed and or calculated in the wrong place (actor, game instance, game state, game mode, player state, level blue print). Or objects are not initialized/constructed and deconstructed/destroyed and the references to the objects are incorrect?

I found the problem. The game mode will only be created and use once the client starts. I just changed the default game mode to game mode base and re-parent my other game modes from that one. So on start the StartMenuGameMode which is a child of game mode base is overriding the default game mode (game mode base) and then when I start/load a game, my WorldGameMode which is also a child of game mode base will be overriding. I have my data in game mode state which my WorldGameMode has and my menu gets the game state and displays that data. It now displays correctly because my WorldGameMode now calls the BeginPlay event which I have initialize the data.