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

This information comes from the same source as all the other information that allows for making changes in the game – from analyzing the game's executable file.
If necessary, I can justify my opinion by showing the section of code containing this error and explaining what features indicate that it is an error and how it is corrected.

If it's obvious to you, then don't bother. The previous explanation, in the form of, if I understand correctly, "the end of the table was perceived as a chance for a neutral zone," didn't seem very convincing. Although, considering how many Fortress units are there, it might actually be true.

Even if it is an error, why doesn't 25% seem like a reasonable chance for a zone without a Fortress? Well, it's not the same objects; it's been like that for a hundred years, but now there are a lot of other objects. Maybe it's not noticeable at first glance, but if you think about it, several elements have been removed from the game. It's a pity.