[Alan Anderson]

You're having problems with some of your PWM signals when commanding high forward power, but reverse works fine? That's a specific symptom with a common cause.

It suggests that your Digital Sidecar isn't getting 12 volt power. Check your wiring and verify that you have a 20A breaker in the Power Distribution board for the terminals you're connected to. Make sure the BAT, 5V, and 6V LEDs on the Digital Sidecar are brightly lit.