Hey there @MOBtx - please accept my apologies that your thread was missed previously, and did not receive a response. The issue you described in your initial post with only one of the two bears appearing to attack Birstan during "An Uncommon Proposition" is one that we had reported to us by other players, and was fixed in a previous title update according to the development team. I hope, as such, that you were able to progress with the quest since the time of your post and complete it, but should you still be encountering any issues with this quest or any others, please don't hesitate to get in touch with us again for assistance! Thanks. 
@Kasnol - Welcome to Discussions! Thank you for offering your advice and insight in the thread with regard to this issue. I am sorry to hear that you experienced a similar problem with the second bear clipping into the ground, but I am glad to hear that you were able to find a workaround and complete the quest. Do let us know if you come across any similar issues again in the future and we'll be happy to investigate further with you! 