Disconnected slabs when I place them in a straight line

[bug reported by my 8 year-old son]

Hello, mojang! I found a weird bug and you can probably tell from the title what it is. if you want to see what it really is, place slabs on the top half of a block and continue in a straight line (in going to the side) and it will randomly switch to bottom slabs which is weird because they are not connected.