That's how it should be! It shouldn't be possible to dismiss a hero with a needed artifact and then dig him up in the tavern. Such things were prohibited by the rules even before! If you want, you can use the tactic of running away from neutrals, or the new possibilities of TE described in the manual.
What are the new possibilities?
The manual is in front of me, and it doesn't say anything except that the HERO is RESET.
What possibilities did you mean?
In the clan tournament, I did just that - I simply RAN AWAY!
Even just because it made the job easier for ME, primarily with hiring the same Hero!
Sincerely,
Prorock.

Как много в жизни есть путей
Для добродетелей и мира.
Я вернулся...