General discussion about Heroes of Might and Magic II.

I haven't started the new campaign yet. What kind of bug are you talking about? I play with autosave enabled. I didn't even look to see if it could be turned off.

Is there a "Wait" command in battle?

As I understand it, the old campaign is the vanilla campaign, and the new one is the expansion campaign.

"Vanilla campaign"? I'm not sure if I understood you correctly. Do you mean Vanilla Ice?
The new one is the expansion campaign, yes.
There is no "Wait" command in battle; you either skip your turn or take it.
Enabled autosave probably refers to the built-in save feature that saves the last turn (there is also an autosave made by fans that saves AFTER EVERY turn, so there are many such saves in the folder).
You don't need to disable autosave.
The bug is related to the fact that in the final stage of one of the campaigns, if you capture castles in a certain order, you get a castle that cannot be captured. This can be overcome by capturing the castles in a different order.