After every call whether its fb or IG or even phone call my volume is stuck on incall volume ! I've had this issue before but it was fixed then suddenly it's back again. I'VE tried every troubleshooting I know. My phone is not in safe mode if you're asking. Samsung should really fix this up ASAP.
Usuall this happens with some calling apps like Messenger, IMO etc. Close these apps from recent apps and it will be fine. If you don't have any important apps open, you may Close All apps.
This is really annoying. I hope Samsung fix this in future updates.