Is it normal that if I die in water, all my items are lost and the gravestone does not work? I find it, but it is just an item without my head on it.

Did you actually break the block and nothing came out?

Same thing happened to me, block appears as item entity floating without name or skull. you can pick it up and place it down, still without face or name. and when you break it with anything it breaks as the item like you used silk touch on it.

@henkelmax, just like @varruzen said :/

It happened to my friends as well, only when we died in water.

Works perfectly fine.