Soulbounded Heirloom

Hi, I've faced weird thing. I mean I find it weird. I used heirlooms while leveling my hunter. Today I wanted to send Ancient Bone Bow to another character and it told me that I cant because this item is soulbounded even tho on its desc still remains as accountbound. Ofc, Ive made an enhancement on this heirloom from engineering ( scope thing, + dmg or crit ) but I guess it shouldnt change the item into soulbounded. My question is : is there a Chance I can remove this enhancement and send this item or it is just lost? Thanks for your time, waiting for response.

Use the lowest level enchantment you can (like lvl 1) on it and it should be heirloom again.