Same here, running destructavator's ufoai-2.3-dev-29004 installer. It's doing it every single time a mission is completed, regardless of circumstances. I tried starting up a new campaign, same thing happened. Everything had been running smoothly for weeks with this build before the bug cropped up, so I tried uninstalling and reinstalling the package. I was dismayed to find that the bug was
still there, effectively preventing me from playing any more UFOAI.