With my a-spinnaker up in 6 knots of breeze I have no problem with my
autopilot, but when I went out yesterday in 15 knots, my autopilot was
not assertive enough to control the boat.

When I set it to keep the 120 degrees off the wind, it completly failed
to do that. Tending to head down, even after the chute collapsed, it
wouldn't return to 120 degrees. If I had not taken control it would
have jibbed.

When instead I set a specific course, it headed up (slowly at first),
not using enough rudder to prevent the boat from heading up and not
reacting at all to puffs that rounded the boat up faster. I repeated
going to standby, turning my boat until about 115 degrees off the wind,
and pressing AUTO again. Each time I repeated this, I experienced
1. The moment I press auto, she instantly reduces the amount of rudder
I was giving by just a little bit, but enough to cause the boat to
start heading up.
2. The autopilot eventually give more rudder, but reacts too slowly to
prevent us from rounding into the wind.

I have a ST-7001, S1G core pack + added gyro, and auto learn feature.
Since the boat handles so differently under sail, then under motor, I
wonder if the "autolearn" feature has taught itself to not be aggresive
enough.

What's the solution ?