It's happened a few times before, that when I trick, I give my item to the other poke, but I don't get one back. I know you might think it is because the other guy forgot to put a item on his pokemon, etc... But no. Take a look at this screenshot.
As you can see, I tricked my scarf to my Miltank, and according to my opponent, he couldn't switch moves. But his Miltank was also gaining lefties recovery. Meaning it was holding 2 items. Also, I tricked with my Uxie, not Drifblim.
Edit: By glitch, I mean bug.

As you can see, I tricked my scarf to my Miltank, and according to my opponent, he couldn't switch moves. But his Miltank was also gaining lefties recovery. Meaning it was holding 2 items. Also, I tricked with my Uxie, not Drifblim.
Edit: By glitch, I mean bug.