mini liquid pump is trying to pump water that is not at it's base

Look at this material view set on liquids :

There's no liquid at the base of the mini pump, but it's in function.

I guess it try to pump the 2 small amount of water on it's side.

(confirmed : once a duplicant had sweeped both of the 2 bit of water on the side, the mini pump stopped working)

Here's the save at this point : Iris.sav