Flickering oil light when braking especially when in reverse

Hello,

My oil light flickers when I'm braking especially when I am in reverse. I've had the car to the shop and they can't figure it out.
The car is full of oil, all the pressures are good. No check engine light. The light does not stay on and when I remove my foot from the brake it goes out. The oil sending unit was also replaced and had no effect the light still intermittently flickers.