This bug has been around since the beginning of Shadowlands, so reporting it here since it's been forgotten about. I previously saw this with some of the tailoring recipes and now i'm seeing it with leatherworking.

Here's an example, I only know rank 2 of Umbrahide Waistguard but ATT gives me completion for all 4 ranks:

There used to be a bug from us that caused viewing other peoples professions to cache their data to your att. try to delete your att wtf files and recache the items.

I've had to recache everything twice since SL came out and both times the bug was still there. Also other people on the discord have had the same recipes give them rank 3 and 4 credit when they learned rank 2. I also have not viewed anyone else's professions. So I'm not gonna go through the pain of recaching everything a 3rd time.

This one is even worse, I'm still on rank 1 and ATT claims I have all 4 ranks.

The more I look at it, the more I think its giving me credit for all rank 4's when I craft a single rank 1. Here's blacksmithing, the only thing I've made is one rank 1 greaves, and it shows that I have rank 2, 3, 4, greaves collected. And only rank 1 of all the others (which is correct). Is crafting an item somehow triggering something that the addon thinks is a recipe collection?

Ok yeah that's gotta be what's happening. I just tested it by crafting a single Shadowghast Armguards. Immediately after crafting it, nothing changed in ATT, refreshed ATT and still nothing changed. But then after a reload, look what happened - all ranks 2, 3, 4 of armguards now shows as collected. (Note that it also played the "you got a mount" music which is really strange, maybe that could point you towards something in the code that is doing that which could be tied to the recipe collection)