Quiver was fully maxed out before the patch. I can't remember exactly but I think it was 32/36/26 when you have max quiver for the bows? I'm down to 12/18/5 (Hunter/Light/Predator). My Quiver still shows as fully maxed.
Last save file with the correct amount of bows is over 50 hours of gameplay ago so that's not a viable option.
Tried the travel to Vinland trick and shoot all arrows then unequip bow and travel back to Ravensthorpe didn't work. But I mean I shouldn't have to do that to begin with.