This crash is killing me, started coming when i migrated to Xcode 12 and even on 12.1, now i have huge list of crashes just because of this. I cant even downgrade because i am using widgets. Please help if anyone finds solution to this problem

I was struggling with the same issue, after two days of research, what i found is WidgetKit Extension needs to be on different bundle identifier. You need to create different certificates specific for widget. Check if widget extension is present in your dependency inside main target build phases. Still if you struggle you need to start with fresh app.