Bug with mirroring hero during town engage via `Fly`

[aaprigorodoff]

After attacking an enemy town, I have to battle with my own attacking hero.
I am not sure if I can properly describe steps to reproduce the bug:

1. use fly spell.
2. fly through an enemy town up-down direction.
3. while the hero is on the town gate map cell, click anywhere to stop the moving.
4. press Space button to interact with the town's gate
   I also prepared a video and the game save (in the zip file)

https://github.com/RoseKavalier/H3Plugins/assets/39566763/4946543a-178b-4a5d-9ba0-b928472627bf
sod_bug_with_hero_mirroring_game_save.zip

I am not sure if this is only sod_sp bug, but i can't reproduce it without the plugin.
sod_sp v1.19.3.14

[RoseKavalier]

This is a well known (yet obscure) original bug which I didn't bother to fix at the time.