Attached is my save file the image of the scenario.
First discussed this here: https://www.reddit.com/r/totalwar/comments/hleglt/balthasar_gelt_iswhere/
First scenario: I recruited Gelt, and he started invisible. I got around it the first time by building another lord and replacing with Gelt after a quick reload before ending turn. I garrisoned him at Altdorf, and recruited some units. After garrisoning for several turns, I was besieged.
Then I sallied forth from Altdorf, won, and chased a fleeing army. When I engaged, Gelt was an invisible avatar but I could still battle. After winning thought, I can't select him from the Lords and Heroes tab. He is shown ATTACHED to another army, which as a lord, should not happen. Neither him nor my Wizard attached to his army is available for selection and can't issue orders, but they take upkeep.
Attached is my save file. You can't select him on the map either. I'm out of ideas and this is irritating that I can't use him.