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

To which version should I revert to in order to avoid desynchronization issues in every battle?

I'm not Baratorch, but I'll try to help.

Version 3.46 was stable. If you're using 3.48 and experiencing problems, revert to 3.46. If you're using 3.47, update to 3.48 and see if that fixes the issue (I haven't played 3.48 online yet, but theoretically, there shouldn't be any desynchronization issues in it).

One thing is certain: version 3.47 is definitely not the way to go.