There are a some issues related to how the game handles the number of pelts in the player's inventory.
(1) The counter will permanently register the number of pelts that have been collected, even if some or all are removed prior to turning them into Aela. For example, if you're required to gather six sabre cat pelts and remove any amount, the counter will still indicate you have 6 of 6.
(2) Once the game registers that you have (at some point) had the required number of pelts, you can still finish the quest without actually having that required amount in your inventory. If you have say two of the six sabre cats, Aela will remove the two pelts from your inventory and complete the quest. You can actually have none of the required items and the quest will still complete.
(3) The counter can display an illogical quantity of pelts if you happen to pick up more than the required amount out of a storage container. For example, it are supposed to collect six and pick up twelves, the counter will display 12 of 6 instead of 6 of 6 like it should.
With other similar quests the required number of items need to actually be in your inventory. If any are removed prior to turning them in to the quest giver, the counter will also decrease and reflect the actual number that are in the inventory. For whatever reason, you can actually have no pelts in your inventory, as long as you had the required amount at one point, and Aela will act as if you have them.
It should be noted that these problems don't actually break the quest. Then again, I doubt they're intentional either.
Screenshots:
https://i.postimg.cc/wvs0BTG5/Screen-Shot204.png
Six pelts were required, but I only had two in my inventory. I would assume that the amount of gold awarded was only for the two pelts, but I don't know how much she pays for each.
https://i.postimg.cc/0j4k0nf1/Screen-Shot200.png
I mistakenly grabbed 11 sabre cat pelts from a storage chest instead of the required six.