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

although I still observe it

in the original, the autobattle differed from the quick battle only by a bug in the quick battle, which was fixed in HD+. And the AI vs AI battle in the original differs from both the autobattle and the quick battle – and isn’t actually a battle. In the original, when AI encounters AI, a certain abstract power of the army is simply calculated, and whoever has more power wins (at the same time, the calculation itself is buggy, and the final result is also buggy – in particular, artifacts are received by the losing hero).

In HD+, the autobattle, quick battle, and the battle between AI hero and AI hero are ABSOLUTELY IDENTICAL (the battle between an AI hero and neutrals is the same as in the original for speed). That is, if magical battles are observed in the quick battle and in the AI hero vs AI hero battle in HD+, then they MUST also be observed in the autobattle.