I get a LUA error when trying to complete a quest. The following are selected:

Enable Auto Quest Completion
Quest Has No Rewards Or One Reward: Toon Complete Quest With Team
Quest Has More Than One Reward: Toon Complete Quest With Team - Toon Choose Same Reward As Team
Override: If Toon Already Has Reward Selected. Choose That Reward

It might be a QuestHelper issue, will try and copy the LUA error.