It's more likely a reporter issue. I don't know why someone would take offense with one and not the other, but if it was reported the mods would only see the reported picture. It's possible a mod just stumbled upon it and deleted it especially if it was recently promoted but that hasn't been my experience on here.
OK. I'll start reporting nude, suggestive, or pornographic pictures, but I may be filling up your inbox(es). Are see-through sheer nighties where you can clearly see nipple and breast considered nudity? Fishnet? There are a TON of those pics. How about bare ass? Personally, I consider the above pics to be suggestive without being especially pornographic. But, your site your rules.
Yes, see-through/sheer/fishnet clothes where you can *plainly* see nipples are considered nudity. So are bare butt pictures. Yes, there are a lot of them, Listal has a major nudity problem that's probably never going to go away. You're not filling up anyone's inbox, that's not where the reported images go. There is a place on the forum that only the mods can see where all the pictures reported by anyone end up for review to be either deleted or rejected.