Updated description by GoldenHelmet April 20, 2020
Beds that span a chunk border can partially break during chunk loading, leaving behind an invisible bed block. When this occurs, the bed head simply gets deleted, and the bed foot becomes invisible. The invisible bed block is bouncy like a bed, but it is non-functional: it cannot be slept in, used to set a respawn point, or claimed by villagers. When broken by mining or with a piston, the invisible bed block drops a bed item of the same color as the bed that disappeared. (Some reports state that breaking the invisible bed block causes a crash, but I am unable to reproduce a crash in the latest version.)
Steps to reproduce:
- Place a bed across a chunk border.
- Move to a position in which (a) you are closer to the bed head than the bed foot, and (b) the chunk with the bed foot is not in your field of view.
- Relog and inspect the bed location.
Expected result: The bed would still be intact and functional.
Actual result: Sometimes you will find an invisible bed block.
Test world: Load test.mcworld reproduces this bug fairly consistently if you set the random tick speed very high before loading (or otherwise generate loading delay). The world contains rows of beds and a system of command block minecarts to automate step 1 en masse for repeated trials. (There are cocoa pods and jungle logs above the beds that demonstrate MCPE-67479, which occurs in the same way as this bug. The world also contains some other structures.)
- To use the world once, load the world and quickly fly up and turn around, like this: Invisibed test world demo.mp4
- To reset the beds, press the appropriate button (marked with signs) west of the relog area.
- Relog north of the smooth stone wall facing the flowing water. *Note: I have found that the bug is more likely to occur when other worlds are loaded or Minecraft is closed in-between trials. I assume this is becaues doing so clears any memory cache that might otherwise accelerate chunk loading.
This bug happens often but I don't know why this is happening. When this bug appears I have to take the bed down and then replace it. This bug is really annoying but I do hope you can fix it.