Where does the Knight Haart come from?

I recently encountered the following problem: when creating a map in SoD, Lord Haart, a Knight, is not visible in the hero selection menu. During the game, he may appear and cause unforeseen events in the scenario. As an example, I am attaching the map. It has two players that a human can control. The red player is given access to hire only Orin, and the blue player is given access to hire only Gunnar. All other heroes on the map are, according to the settings, prohibited. However, if you choose a multiplayer game, you can see that the red player has access to 2 heroes - Orin and Haart (and again, if Orin is hired first, Haart mysteriously disappears from the tavern). Could you please advise on how to remove this hero from the map?