I load into my world constantly being invisible gear and all, there has been several times when I have dismounted my horse and it disappears, vanishes.  I have to log and when I come back it's there. 

I died in the neither with enchanted netherite tools and gear, I respawned in overworld to run back. My brother died shortly after I did trying to secure my stuff, and didn't press respawn to watch the items. Within 2 minutes of him dying all the items disappeared. And five minutes after that I got to the spot and all of the items were truly gone! WHAT THE HECK!?

I have left items in the ground for a Minecraft day or two and they have still been there, when I was in non-beta. This should not be a glitch and I'm pissed I lost that gear because of despawning rate spiking all of a sudden. I've had similar situations and they items where always there when I got back.