TU 211867: Dupes jumping through wall to deconstruct valve.

That's not a wall though. That's a gas permeable tile. Those have had quite a few bugs related to its cell collider.

Like as far as the simulator knows there is only a gas tile there and the game is telling the simulator to prevent liquids from flowing there. Quite possible that there is some code that is forgetting the cell collider check.
 

1 minute ago, Risu said:

That's not a wall though. That's a gas permeable tile. Those have had quite a few bugs related to its cell collider.

Sorry, you're right! I personally consider them walls (of sorts), hence the mislabeling. I'll go back and fix that.

In regards to duplicants it should be a wall.