Slightly concerned that it takes a very long time for engine oil to return to the sump.

After running the car the oil drops from the max line of the dipstick to about 1/4 over minimum.

When the car is stopped it takes a good 6 hours for the oil level to return to normal.

Anybody had this before and should I be worried, oil never drops below minimum but I'm guessing there is a blockage somewhere and I don't want to starve anything of oil.