game crash item duplication and deletion

I was in a multiplayer world today. My brother was playing (and hosting) the game on the Nintendo switch. I was playing via a LAN connection on an Amazon Kindle Fire. Suddenly, the game crashed on the switch end ("The software was closed because an error occurred") and I was forcibly ejected from the world. When I logged back on, it (naturally) set us back to the last save point. Now, before the crash I had taken some iron out of a chest, and used it to craft a replacement for my badly damaged enchanted sword. After I came back from the crash, all 17 of the iron (not just what I had previously used) had disappeared, as had the new sword. As if this wasn't weird enough, my damaged enchanted sword now appeared once in my hot bar... and once in my inventory. I'm not even sure what to call this?

Also, I don't know if it's related, but I used a nether portal right before the crash.