Your merchandise inventory have been corrected, your sales proceeds (sales, COGS & returns) have been recorded. This is to record payments for your outstanding AR. Who would you question if it was not a mistake?

If inventory was corrected, then you need to question the person that conducted the first inventory.
Also you need to question the person that posted the first inventory into your records.

I don't even get it. Your title mentioned contra revenue, which could be your returns. If there's not a mistake, why are you questioning anyone?

"This is to record payments for your outstanding AR." This what? Is this somehow related to the mistake that isn't a mistake? Are you recording this entry? How is a payment of outstanding AR related to inventory mistakes?

You can question the people who had anything to do with inventory, but I find the post thoroughly confusing because I don't see what the rest of it has to do with correcting inventory, nor do I see how recording payments of AR has to do with anything else. It's like a big mishmash of information.