This has happened multiple time and it's really starting to get on my nerves. It seems that when you're killed in a confined space, some of your items fail to drop on the ground correctly. It's never all the items, but there's always some of the items that either fail to drop completely or despawn upon colliding with a wall. The first few times it was only a few items, like a dia pic or a stack of cobble or something, but this time it was my entire inventory except for my armor and shield. I stepped away from the game for a minute and lost three hours of progress because I couldn't collect my items, it's incredibly frustrating. I've noticed it only happens if there are blocks above floor height within reach of the player's death, which leads me to suspect it's a collision error that causes items to fall through the ground; however, that is purely speculation and I cannot guarantee the missing items even drop when I or someone else dies. 

This has all occured on my Singleplayer bedrock world that my friends occasionally join, and while I've had this problem in earlier versions I've never lost an entire inventory before.