i haven't been able to test too many companions yet, but it looks like the rewards from companions might not be properly scaling with companion level. the last 2 bonds with my basidio at levels ~6 and 9 yielded 7 and 10 xp, respectively. i remember from beta and ea that the xp still varies, but was definitely higher than those lvl 1 amounts. i also remember item-granting companions not functioning correctly on level up during ea, maybe the bug has spread?
other people playing with leveled companions: are you seeing the proper rewards increase? i might have just gotten insanely bad luck rolls.
update: my lvl 10 basidio gave 25 xp, and my lvl 10 simburr did give an item in addition to pebbles, so i might have just very unlucky. exp is still on the lower side of what i remember though.
update2: the lvl 10 basidio just gave 7 xp, so i think something is wrong