Nano cup doesn't seat right - does this Nano body look normal?

[agoutihead]

I've had this Nano skimmer for years now and never had any problems with the cup seating perfectly up until recently and not sure why.

Does this look right with this hump/bubble? Or did something happen and the plastic warped?

 

[rvitko]

Yes, that is the deflector dome, but the cup should be over the hole, the pump is aimed at the dome.

 

[rvitko]

Pull the air hose down from the bottom to seat the lid, otherwise the hose will be trapped in that top chamber and act like a spring pushing the lid off.