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

I don't understand why it's illogical.
The point is that when Enter was pressed, control was passed to the left hero, and now it's passed to the right hero. To maintain compatibility with the old version (so that the heroes don't run off in the wrong direction), it's suggested to switch the focus from the right to the left button. And not to swap the buttons.

Exactly, that's what it was about! In essence, this is very critical! The main hero keeps running off the route because of this!

If you click on a creature without Shift and then on an empty slot with Shift, it will be a classic split...

With this sequence, it worked once or twice, but then it stopped working.
Another bug. During the opponent's turn, the image of the hero's mount (for some reason, the main hero with a large army) disappears on the map, but it's still visible in the list.
And when in a town, the image of the adventure map becomes transparent (in the same place as outside the town).
And sometimes the system game sound (countdown of the last seconds, opponent's turn) disappears.