While not technically a bug in the sense, as more along something that was changed to combat twinking, and never changed back when real fixes came out making them all just “scale to level” anyways.
Shoulder Inscriptions, Leg Armor Kits (enchants), Leg Armor Spellthreads, and I believe scopes all are stuck with that “requires level 80/85”. Effectively forcing you to level a character specifically somewhere between level 80-98 to apply them to your heirlooms to pass back to your little characters. Anything higher, and the heirloom is too high an ilvl to enchant.
It seems kinda off to require someone to create a half leveled toon in order to use certain enchants on other characters.