HoMM3 HD is a mod (add-on) for the game Heroes of Might and Magic 3.

NO!!!

Don't upset the Polish guy. It's a known bug – I encountered it often in one of the pre-release versions of the mod; then it seemed to disappear, but I encountered it twice in the latest version. Moreover, it works both ways – for example, I took a Conservatory of the third level, there were two angels, I transferred an army from heroes, and there were 4 angels in total. I had to feel stupid, explaining the reason for the auto-save. Not long ago, the number of birds decreased by 1 when transferring an army. Again, for no reason. I think the reasons are similar.