Sometimes MI A1 A2 and A3 Incoming Calls are not showing on the screen but phone ringing. This problem is resolved now. I have Mi A2 and same problem, Incoming calls are not showing on display, but now its resolved.

If incoming calls not showing on the lock screen watch my video and get knowledge on how to show incoming calls in the android phone(mi A1, A2, A3). Phone ringing but nothing on the screen, it happens in lost of mobile but it's a common problem.