Unable to pick up items upon death & respawn, or items disappear

Upon death by falling from a high place; my items will be on the ground near where I died but only some of the items are actually able to be picked up off the ground. About half of my items are floating above ground and will react as if they are actually in this location but can't be picked up. I can lower them father into the ground by removing blocks; I can raise them above ground by adding blocks; I can shift them by placing water from a bucket but I can't pick them up. 

 

This has occurred twice in a row when dying by falling from a high place but the third time I tried recreating the situation everything was able to be picked up normally. 

 

Update: Died by skeletons at a spawner and two of my pickaxes and three stacks of blocks are doing the same bug. My inventory still has a full 9 slots available but I just can't pick some items up. 

 

I am the host with one other player who has joined me.