Same here. I started my flight cold & dark on the water. At first I couldn’t even take off at more than 90 knots until I put in full flaps. After that the trim simply doesn’t work, even though I see the animation on the yoke when I actuate it. As soon as I relax backpressure on the stick, the Seastar goes into a nose dive.
P.S.: the autopilot can’t hold the altitude either. It results in a nose dive as well.