Moscow, turn it on :rolleyes:.

Information about heroes in the save file is stored twice - in the header and in the body of the save file. This is why glitches with heroes occur - gray color, duplication, and other oddities with dungeons. Many people who analyze save files even suspect that someone has been messing with the save file using clumsy methods.
I'll take a look in the evening, maybe I'll be able to make a level 10 hero in a dungeon, and then dig up the same hero, but level 1, in a tavern :)