Greetings, Zerstoren!
Thank you for posting your concerns about leveling your Adventuring Fellow NPC. It seems that Shadowheart brought up a good question that may help with this investigation (thanks, Shadowheart!), so it would be greatly appreciated if you could go provide further details regarding the completion of the last level cap quest for your Adventuring Fellow, including the names of the NPC's that you spoke to and the items that were involved. The more details that you post, the better chance that we have of possibly replicating this trouble that you have been experiencing. Thanks again to both of you for your participation!