The enchants that backpacked add (Marksman, funnelling, repairman, looted, imbued hide) can be added to any item (picks, swords, even create's sandpaper). The impact is minimal but it throws off the statistics when you find or enchant an item.

I'm using Fabric 0.16.7 on minecraft 1.20.1

just noticed the same, please fix, it leads to a lot of frustration. also the backpack does not seem to even be enchantable from what JEI tells me