Had a similar thing happen, but when I hit the transfer to ship it sank under water instead of flying up. In about a minute the bear was dead. About an hour later the same thing happened to my tiger, but i swam down under water to it and tried to mount it, call it to follow and nothing it was stuck. I happened to realize the anchor was resting at the same depth and immediately swam up and raised anchor and the tiger quickly surfaced and appeared on my ship. So at least in that circunstance it had to do with the anchor.