General Mobile 21 Plus (Android 12) is automatically restricting some apps battery usage without my permission

I'm using General Mobile 21 Plus on Android 12. Sometimes I notice that some apps are not sending me notifications or the notifications are delayed. So, I go to Settings -> Battery -> Battery Manager and I find Android had restricted the battery usage of some apps, so I go and uncheck the restriction on those apps and now the apps should use battery without restriction. The notifications are now coming as expected. After a while, I find that Android had again re-restricted some apps without even asking me. How can I prevent that annoying behavior and prevent Android from making these choices without my permission?