After about 20 minutes of steady combat (using lvl.80 ranger at slippery slope map) the Companion Bonus Skill 'Baby Owlbear's Presence' procced, but only 1 time and for a very tiny amount of damage. Its certainly doesn't seem to be working correctly yet. Also, I could be mistaken, but I believe when the 'Baby Owlbear's Presence' procced it procced from using an encounter power, (probably cordon of arrows or plant growth). I found that while testing using only 'at-will' powers the 'Baby Owlbear's Presence' did not proc at all.
1