None whatsoever. You can't cause oil starvation with a higher amount of oil running thru the system. There will be no effect on oil pressure either. Starvation can only occur when the oil sloshes in the oil pan and uncovers the oil pump.
There will always be oil in the cooler as the mocal and other thermostatic plates, allow 10% flow rate and is never shut off completely. This keeps the system free of air pockets. Think I mentioned this before.

However, the additional 1/2 liter of oil will not cause a surge or reduction in oil pressure.
Oil pressure varies as the throttle is utilized. As oil becomes more viscous when hot, oil pressure reduces overall. As the oil pump is mechanical and increases it's pumping velocity as rpms raise, oil pressure is constantly changing with the throttle setting.
Normal oil pressure usually varies from; 25 to 65 psi, when the engine oil is at operating temps. It can be higher when the engine is not warmed up, especially during colder weather. Anything over 80 psi, when the oil is up to operating temp. Then you've got a problem that needs to be resolved. There is no static oil pressure psi rating.