1988 30hp Yamaha 2 stroke leaking oil at lower unit (pic)

Over duck hunting season I noticed this same leak coming from lower unit when tilted after fishing today. What I did before fishing season was replaced gaskets on water pump housing and replaced the water pump. I then did a vacuum check on lower unit at 10psi for over 15 minutes and it held. I drained lower unit last week and noticed the brown color coming out that I noticed with the leak. I replaced lower unit gear case oil with blue color. When I noticed today that same brown leak today after fishing I decided to drain lower unit to see what color it was. It was still nice and blue. Any idea what it could be?

This question is asked many , many times.-----It is normal.----Some fuel and oil goes right through the motor into the exhaust.