Important oil pressure light question

I just got an oil and filter change. Now every once in a while the oil pressure light will go on. It usually happens when I'm idling at a light and goes off as soon as I accelerate through the light. This never happened before, the oil is full and there are no visible leaks. This is the second change that I am using mobil 1 could that have something to do with it? The manual says that "the light can come on briefly, which is normal and doesn't show a problem", but I never saw it before. Any help would be greatly appreciated!

Has anyone else had problems with mobil 1 in an older engine?

I would guess the sending unit has seen better days