Slabs flip positon randomly when placed on multiplayer servers or realms

To reproduce: Join a server or realm and start making a platform or bridge with top-facing (or bottom) slabs of any material. After a while you should notice some slabs on the bottom position or vice-versa. In my opinion this should be considered unintended behaviour and should be fixed as soon as possible as it's very annoying and can cause resources to be lost in some cases.