I found an interesting thing - when I load the attached position and teleport
back to the town, all NPC and bots are damaged.

Did you change the game difficulty in the option menu between saving and loading
the savegame?
Because that is what causes such issues very easily.

Yes, I did. So I think it explains that.

Renaming to reflect the problem.

I think the way to solve this is to keep track of the difficulty settings for
every save game.

Then:
1) On save game load, if the difficulty settings have changed, we should scale
the health of all NPCs and bots to reflect the new settings.

2) Or we could make the difficulty setting persistent for a single save.

salimiles: I don't like the second option. If the player was playing and found
it too hard, he/she should be able to switch back to 'easy' as well.

In my opinion, we should save the difficult setting on the save game, and if
it's different from our current, call a function to update everything (HP bars,
etc. I already got issues with updating HP bars on my increase_difficulty() patch.)