Oxygen plays a part in the way oil based coatings cure, but not in latex
paints. The only oxygen to dissolve in wet latex paint would be
whatever oxygen goes into solution in the water the paint is thinned
with, and that's not gonna change while the can is in storage.
So, there is no good reason I can think of for the semigloss paint to be
under any kind of pressure. And, to be honest, I've never experienced
that with any kind of paint can I've opened; oil or latex, glossy or
I suspect it's just the can you're using. Home Depot sells empty paint
cans. I suspect that if you transfer your semi-gloss paint to another
can, the problem will disappear.