Oil light blinking on Audi A3
 

The oil light of my Audi A3 8P 2006 is blinking after my car comes down in rpm, mostly after leaving the highway and driving in to a parking lot. The light is starting to blink after going from 110 km/h to 30 km/h. It’s a 2.0 petrol, no turbo. We have tried to change the oil but the issue remains the same.
Anyone knows any solution to this?