The Axistence tier still shows up when you search the market for "rare."
I also passed a Bat that displayed as orange in the crate, but it still shows as a legendary.
This is unfortunately a side effect. Any items on the market pre-change wont be directly updated. I'm not going to go through each one and update it's rarity in the database at the moment XD.
Not a valid bug or unable to resolve. Locked.