Please re-open this issue, it is NOT a replica of MC-87194 as some said, it works differently and occurs under COMPLETELY different circumstances. Also, that one has supposedly been fixed, while this one is still happening, and breaking my world.

Whenever I log out of any world, oak wood and cobblestone stairs that I put down next to purpur stairs disappear when I leave the world and come back in. They leave the block where they were darkened. This happens with the stairs in any orientation. It does not happen to any other kind of stairs, only oak and cobblestone.

To replicate this effect, open any world, put down purpur stairs, then put down either oak or cobblestone stairs one block either beside, above, or below them. Then, close the world and reopen it. The oak or cobblestone stairs will be gone, leaving a darkly lit patch.