I thought that there was a bug in the bookworm quest, first one if there's more than one, but I just hadn't tried every combination of choices yet. You should provide the option of sharing with the gribler being beaten a second time. If you try to talk to him first, you are unable to then also share with him. I think you should allow the choice to share with him to be available after trying to talk to him. It's more real that way.