Slabs compile into one block when they can't be placed due to collision

[Thylaluna]

Im having trouble where sometimes slabs will compile into one block, the animation and sound will play for the block placed but it doesn't appear and still removes it from my inventory. After breaking the block I get all the blocks back at least but its annoying to deal with.

[TriibuNupsik]

When it doesn't place your inventory gets desynced from the server. You still have that item in the slot but it doesn't show on the client. Try to click it in the inventory to resync it.