Hunting Request Glitch (begging you to help)

[vsvp]

Hey y'all!

I've almost finished the game for 100% (it's% 98.5 rn), but I'm facing a real trouble. It's the third request from Mrs Hobbs and the last thing I need to get is a perfect opossum's carcass. Every time I find this little bastard, I get the perfect version of his carcass, all good, 3 stars. But the point is - it doesn't count for my hunting request, like I didn't get the carcass. I've tried to get different opossums from different places but it doesn't work at all. 
I've reinstalled the game but nothing as well.

It's been a few months since I'm trying to get platinum, but seems like it was just a waste of my time if I won't fix my current trouble. So if you have an idea how I can solve this - let me know, I'M BEGGING YOU! 💚

[Anthony]

First, you have to kill it with the varmint rifle to avoid damaging the pelt too much. Then, you have to TAKE it on your horse and send it at the post office: you DON’T have to skin it

[Foxtrot]

Have you looked in your mission checklist to see whether the animal is mark as checked off?  Sometimes you don't get the on-screen message for every animal you've collected.