Sometimes when an army with only one hero in it gets attacked, only that hero shows up for combat.  The rest of the army is missing.  Then, when I get defeated, it shows everyone as having died.  However, they didn't die, they just teleport to whatever city the hero goes to to recover.  So, while at least I'm not losing my army, I'm still losing a fight that I probably wouldn't have lost otherwise.

I've seen this issue sometimes on prior versions as well, but this time I got a screenshot and more closely paid attention to what happened.  Unfortunately I haven't figured out how to reproduce it, and reloading a save won't work because of the bug where you never get attacked when reloading a save (also because auto-save seems to save at random times now).  In order to get a usable save, I'll have to quicksave before ending my turn every turn and waiting for it to happen, but it doesn't happen often (maybe once per game).

First screenshot:  The combat where you can see that my champion stands alone.

Second screenshot:  The defeat screen after my champion died.  This particular combat I would've lost anyway, but I've had it the other way in previous games.