Assertion Failure, Do you want to Debug? AI Core Exception

I've been having issues today with Character Animator—I keep getting the pop-up, "Assertion Failure, Do you want to Debug? AI Core Exception. Yes or NO?"

I don't know what this pop-up means, and whether I choose "yes" or "no," neither option seems to make a difference. If I say "no," it will let me continue to work in Character Animator, but then when I try to import into After Effects to export with an alpha it crashes After Effects. I also tried to import the Character Animator Scene into Media Encoder to export it with an alpha from there but the encode just hangs there and never begins. I thought it might be a corrupt Character Animator project so I started over fresh but as soon as I started to import artwork into a new project it gave me the same pop-up, "Assertion Failure, Do you want to Debug." I feel like I'm in the worst M.C. Escher lithograph ever made. I've restarted the computer, uninstalled Character Animator and After Effects, and nothing seems to help. 

Any suggestions, Adobe Community? I've looked at prior message boards but I haven't found a solution to this particular issue. Any troubleshooting ideas are appreciated!