Been noticing a lot lately on items that I deal with or Items that I just see aren't actually being updated when traded.

I first looked at my bookmarks, many were completed, so I took a look to find that the history stated that the item was still in the person's backpack. I'd click the inventory link to find that the item actually isn't there. So I used premium to find it, thinking that maybe it had been bought by someone with a private backpack or something. Surprisingly, it had not and the person who bought it had a completely non-private profile. So I thought maybe it's just a one off bug. But recently I traded a few items to someone with a completely non-private profile and the history still says I own those items. I have tried this from multiple locations, logged in, not logged in, different internet connections and nothing, it's all the same.

So I'm wondering, is it only me having this problem, or is there an explanation for this problem? Thank you for your time.