That's not Jingo. It shouldn't be like that. Apparently, it was initially designed so that only Dorian could take the key from the dragon, and no one else. I don't think this is a good idea...
Yes, it seems to be built into the game. Do I like it? No. Can I do anything about it? No. Was there something for my character to do during the expansion other than dominating dragons and completing the main quest? Yes.
If I could, I would create an expansion where a character like Jingo could casually explore because the difficulty level in my expansions is significantly lower. But unfortunately, I can't.
Небо – угроз не слышит
Небо – ведёт особый счёт
Небо – тебя найдёт