It seems like three different instances of this bug so far, then:
- Dead units lingering permanently.
- Dead units lingering for one or two rounds.
- Just encountered now in a local game: I conquered a Beastmen city, and there was a blank unit icon background in the army list on the overland map; there was no actual icon on it, just the background. When I clicked on this unit, the game crashed to desktop, no error message.