Air filter housing

[degzi]

I have just had a look to see what condition the air filter was in and I have noticed that the rubber on the air filter has been nipped when fitted.

The corner closest to the battery.

As a result looking at the plastic housing it fits flush all the way around except this corner.
So my question is this. Should the plastic air filter box fit flush all way around or is there what looks like a slight gap in that corner.