As per this from patch notes Leveled items such as spirit stones or items with planar levels will now inherit the Heirloom tag instead of the No-Trade tag once they have gained experience. Neither Spirit stones, NOR leveled items Planar Items are Heirloom currently once Levelling have started/completed. As per above, these items should now be Heirloom once levelled. (For the sake of spirit stones they should be heirloom once unadorned AND levelled, Planar items it is assumed would be heirloom once levelled with no extra steps needed as per above. To Reproduce, apply a currrent/previous spirit stone to an item, gain experience and unadorn.