Update- it appears to be any block. I broke a cobble stone block with one on top so I destroyed the bottom and made a floating block and I can snap into it and start drowning. Worked for cobble stone and iron just to verify it wasn't one block. It could probably kill me given the right circumstances. You could definitely make a trap with this though.
M trying to upload a photo but it's not letting me
Can concur.
Can confirm, updated to beta and was wondering why it was so lagging. I disabled the fancy graphics, render distance and such to no avail until I read this bug. Took the elytra off and it's sticking around 50 to 60 fps
Can confirm. Confused me had this morning