How to fix bugs that only occur on build?

I've got an in-game glitch that only occur on build, not in the editor. Wondering if there's a way to check that out. There's no debug.log or anything of the sort, so how could I isolate the problems? My thoughts so far would be to change things here and there and build the game to see what works. Just randomly do things and build every minute along the way. So far this doesn't seem to cut it. Are there more efficient ways to peek into the system at build-time??? -Unity 2019.2.17f1 LWRP -(It's a screen flickering and going dark, in case you're wondering.)