Chlorine duplication bug (may involve wheezeworts)

I've build a wild farm to grow mutated pincha peppa's, filled it up with chlorine and added wheezeworts.

However, the gas pressure in the room has increased up to 80Kg/tile in some areas.

Initially I thought it was related to bleach stone being stored next to the wheezeworts. After removing the bleach stone from the room and installing a gas pump to remove the chorine initially the pressure dropped down again. But later it increased up to 80KG/tile again.

I don't understand where this gas could be coming from other than some kind of duplication bug.