I haven't tried this on other pets but mounts such as ostards, horses and llamas sometimes don't transfer when "x transfer" is spoken by the owner. It asks who to transfer to but when you select the new owner nothing happens. This only happens sometimes, other times a trade window appears with an icon that looks like the animal you are trying to trade.
My suspicion here is that the creature may be failing to obey your transfer command, and this may not be noticeable by you because its often a common feature that most players have enabled in razor, to filter out animal sounds, mainly horses. I'll try to reproduce this to verify exactly what is happening, thanks for the report.
I was using a character with 100 animal lore and 60 shown taming to transfer a horse, the reason why I think its an error is because it fails repeatedly when the error is occurring (even after 10+ tries) but if I try it at another time after some more playing it works fine on the first try.
This must be connected because now I am trying to release a mount and everything works until I press Okay on the gump then nothing. Mount is still mine and the animal counter thing still shows 2 (I am riding one and trying to release the other).
