if you try sleep at the bed and wake up (regardless of full night sleep or interrupted), you can wake up inside of some blocks.

I tested out to chest, enderchest, shulkerchest, anvil, scaffolding, armor rack, and normal solid block. I could not find the similarity in trend, so I stopped testing from there. result was:

• I could not wake up inside shulkerchest and solid block.
• I could always wake up inside armor rack and scaffolding
• I could wake up inside chest and enderchest if the bed is placed toward -x direction against the wall the bed is perpendicular to.
• I could wake up inside the anvil in the same condition to chests, but in addition to that, -z direction also did work. However, anvil has to be positioned parallel to the wall. (Please have a look at the picture attached to this report.)

Description about the picture.

if I count 1 from the left most bed, 3 and 4 are the beds that I can supposedly wake up inside. However, as I described at the fourth entry of the upper section, I can only wake up in the anvil in the number 3 case, but not number 4.

I noticed this bug in my survival world, and tested it out in the creative testing world. Hope this brief testing result can help you sort out the bug.