After i installed 0.11.0 Beta 8, i encountered a cave on a small island and removed some of the sandstone ceiling with a pickaxe.

After two blocks, sand fell - and dropped (it was or became red sand. Thats interesting, as it was a rather normal biome - ocean all around, a smallish hilly island.I thought red sand would be mesa exclusive)

When collecting the fallen blocks, the game was force closed. Same happend after restarting the same world: The red sand items were still floating in front of me and collecting lead to another crash