Autopilot turning too early for track course

[stevemitchell]

I have a p70s, EV1, and an ACU-100 connected to a mkII wheel pilot. Controlling all of this is an es78. All are running the latest and greatest software. They are all connected via SeaTalk, which is also connected to a NMEA 2000 network. Speed through the water is provided by a NMEA 2000 Maretron DST110 triducer. A complete network diagram is attached and also available at https://sailbits.com/grace/

Using a manually created route, or one via Navionics Autorouting, the MFD is advancing to the next waypoint in the track/route too early, sometimes dangerously so.

This happened 6+ months ago as well, and I did a complete factory reset, dockside wizard and commissioning, and changed the speed source to SOG, and things worked for a while. I think I found a post on the old forums or elsewhere that gave me this guidance.

With this configuration, should speed input be set to SOG or to the STW provided by the DST110? Is this the cause of advancing too early?