Title

It doesn't stop taking durability, the durability is just hidden, and it breaks up into old running boots, ignoring the item tag.

Hey there, it looks to have been fixed for current version of the mod, 8.1.2, as this is the case I am going to close this ticket.

All the unbreakings slow it down, as intended, but do eventually take damage.

Hello! You refer to the enchantment "unbreaking" which is not what I am referring to.

I am referring to the ITEM TAG, "UNBREAKABLE", not "UNBREAKING".

Sorry for the double post, but I figured I'd provide additional explanation. Once again, this is NOT referring to the "Unbreaking" enchant, instead referring to the "Unbreakable" item tag, which is supposed to make items unbreakable, not taking any durability. The new running shoes do not respect this tag.

For example /give @p pixelmon:new_running_boots 1 999 {Unbreakable:1}

Even though Unbreakable hides the durability, this will give you New Running Shoes with one durability point left. Notice the "Unbreakable" text below the item. Now run with them in survival. They will break into old running shoes anyways.

I've wanted to provide a way to sell permanent new running shoes on my server but due to this bug I have been unable to.

Third post. Sorry, looks like somehow my fingers typed "Unbreaking" despite the fact I was clearly thinking of "Unbreakable" in my head.
Stupid hands...

Confirmed this in 8.1.2 with the new information. Seems to tick down the durability as if it wasn't Unbreakable. During tests it took about the same time as going through regular ones in a Movement Plate loop.