When you make an underground bed, please dig some space out around it, if its just a tiny hole with an exit the spawn code is going to get confused and move you up or down. You don't want that, I don't want that, your infinite death loops can be avoided.

Chests need to be buried at least 8 blocks away from any players to be x-ray proof, no your hidden chest under the floor is not safe. Proper dropchests need to be 8 blocks away from where any player will casually walk and next to stone (as that is what they will be disguised as, while you could bury them in dirt and most x-ray clients won't show them, the smart x-ray'er will look for the odd stone block in the middle of the dirt)

Finally when the server is laggy or otherwise acting strange, don't suddenly decide to move all of your wordly wealth into or out of your inventory. Just leave everything where it is and its far more likely to stay there in case of serious server problems.

Just saw a lot of these in modmail.