[dalew]

FWB, my cap appears to be the same as yours.
I did notice that I could push down on the cap after it reached the latching point and it could be pushed down somewhat before it contacted the sealing rubber. If the cap is vented, where is the vent? Mine does not seem to sit tight to the rubber seal. With the cap not sealing tight to the rubber would that be how it is vented?

Thanks for all of your replys