I have a Samsung Note20 ultra 5G. I often witness my YouTube, video player and some other documents minimize by itself why working on them. Don't know why it keeps happening
It's supposed to be a feature- as in multitasking while watching YouTube, etc. I'm positive you can disable this setting (I'd have to play around with it a bit but I'd start at the App Settings itself). I find it convenient honestly- if I'm in the middle of something and get a phone call, I can continue on with my doc edit without any issue.
Oh! I'm sorry, it didn't even register in my side that you had mentioned 'while working on them' (ex. watching something or working on doc itself). That is extremely irritating, I'm sure! Has it been doing this since you purchased it or recently after an update?