Some blocks are getting removed in the latest snapshot after exiting and reloading the world. After expiramenting, I found that these blocks include but may not be limited to Oak Wood Stairs, Cobblestone Stairs, Oak Doors, and Iron Doors. They don't break and drop, they're just gone.

How to reproduce:
1. Place Stairs/Doors.
2. Save and Exit.
3. Reload World
4. Blocks are gone.

And after multiple tests, I found that sometimes only the bottom half of the door is removed and a shadow appears where the blocks used to be.