use [, not (.

It isn't passing through wide diamond, it's passing through one pixel spaces, like any other element

I think it's because the expansion and pressure moves the gas several frames at once, making it not detect the diamond.

EDIT: Neospector, I fixed the walls and it acted in the same way. The damage the to wall had no consequence.

@scarface
I see what you mean now. Probably just a normal glitch, like bomb destroying black hole, white hole, ect.

You first posted this. It's not the first time I've seen wierd things(like extreme pressure sending diamond flying 20 pixels in a single frame, and yes moving diamond.)