My druid is level 8, but has a level 5 animal companion. Everything I've read tells me the companion should level up with my druid. Is there a debug to fix this? Adding and removing the feat has not helped!

Just going to add some more info, because I think I've got some real problems here. I'm playing Storm of Zehir. I'm playing totally unmodded, clean in stall.

My ranger has Natural Bond, and is currently Ranger (11). My companion is Beast (7). That makes absolutely zero sense to me. As I understand it, ranger is -3, and natural bond is +3 up to my hit die for determining level of animal companion... so I should have a Beast (11) companion, should I not? Something is definitely weird in my game.

The animal companion is not supposed to have the same level as your character (except at 1st and 3rd level). You can check the intended level progression on the NWN2 wiki.