I had something similar happen to me around the time the last patch hit. I actually tried to reload after getting into a hard battle unprepared, but the recent quicksaves all said "this savefile is corrupted". So I finished the battle and they were gone entirely, but I was able to save again and it hasn't happened since.

So try playing again and see if the problem is still there.

I don't use quick saves (maybe I should), I actually type a name for each manual save and save it, but then the game erase every save except for the last autosave. It's been happening to me for the past few days, on at least 5 separate occasions. :-/

Just some additional information about this bug:

Text, Menus and Tooltips
Inventory scroll arrows not working outside of a castle: The fix to the inventory scroll problem inside castles has made it so players can't scroll their inventory anywhere else; the scroll arrow is greyed out. Workaround: click inside your inventory and use the mouse wheel.

Inventory outside castles behavior: If I first click the Up Arrow button to show my army, then the Left and Right Arrow buttons work as intended. Also, if I scroll to the end of the list and then click the Down Arrow button to hide my army, I can click on the Left Arrow button until I am at the top of the list again. After that the Left Arrow button becomes disabled again. The Right Arrow button is always disabled when the army is hidden.

Another note about the changed battle objects: Powder Kegs have 0/1 health and explode instantly as the battle starts.

When I kill a "kamikazed" stack with assasin backstab, the bomb doesn't detonate, and the game freezes before the next turn/round.

But those battles definitely counts at least for one thing - to increase the "Guardian" counter - just checked by leaving one friendly goblin and spamming the stone skin spell.

@Handel
Yes those fights will count spells cast , rage spent toward medals/achievements. But battle itself wont count toward anything.

i don't know if ii's only my bug or it's suppose to be that way
royal griffin get -2 for having dragon(ice dragon) in the army. BUT i have persuasion 3( -1/2/3 =0), and yet -2 moral for royal griffins

Could you please add these are they are introduced with build 6249 and previously worked fine.

Pygmy does not work properly now. It reduces the health of enemy stacks to 1 HP per unit instead of -20%/-30%/-40% of their max health.

Whenever a demon kills a stack, a rage ball is supposed to appear and it can heal all demons on the field. This no longer works now.

The random 1 HP issue can occur when no one is using Avenging Angel the spell. This is PROBABLY because The "Favorite of the Gods" passive that smites back enemies says it is an "Avenging Angel" skill. So the bugs are probably interelated.

Thanks so much for the summary, these are all added. I've been busy with the U.S. holiday weekend. If you can let me know the exact name of the trait which is not working for the demon I'll update the list with that information.

@ivra I've updated the inventory bug entry.
@Nirual I've updated the powder keg entry. I also noticed skeleton coffins have 0/1 hp but didn't get to test it to see if it opens automatically. If anyone can test it, let me know.
@Ufozile I've added an entry for Kamikaze. I tested it, too, and it's happening for me regardless of what kills the target stack. I used it on bowmen and killed them with a spell and the bomb just hovers there, then hangs up the game when the next turn starts. Ugh.