Unique and Legendary are overlapping categories for stash tab priority

Considering that once LP has been used on an item (or affixes added through Nemesis, etc.), the item type changes to “Legendary” from “Unique,” why is it that stash tabs can’t differentiate between the two? I have one stash tab category that includes some legendary priority tabs, and a different category that uses unique priority tabs, and whichever I am viewing is where these items land when transferred. This means that the “rarity” option in the tab priorities is just not working correctly.