I'm in the same boat with a late 2019 version of Android Studio (v3.5.2), and I've been using it a couple of years, so it seems like a new problem to me. I am able to resolve it by either 'wipe data' (undesirable, often) or 'cold boot' (from tools->avd manager) and then running the app. However, this is not a permanent solution, because it always comes back. I usually wind up doing the cold boot thing once, then be careful not to close the emulator while I am debugging so it is good until next session.
I will note i noticed Android Studio was HIGH on memory usage (which is more difficult to notice in SSD times, because you don't "hear" the hard drive thrashing from swapping memory.) Android studio itself noticed the abnormally high memory usage and reported this to Google (presumably). I wonder if low physical memory is/was the issue.
Update: I just had a BIOS update for my notebook, and afterwards, I do not seem to have the same problem. It is not clear if there was a BIOS problem (virtualization, which emulator uses, is a BIOS option) or if it was just the reboot which temporarily cleared up memory (my original guess).