I just bought a new boat (year old) with a 250 SHO. When I fish shallow and trim the motor up out of the water I noticed after about 10 minutes it starts to creep back down into the water. The last boat I had was a 200 vmax and I don’t recall having that issue. Is this normal? My first thought is that I am low on trim fluid or have a busted seal or something?

It Trims up and down just fine, not slow or lagging and when running it trims just fine up and down.