Hello Mark, I had a similar problem with the 6924. I don't know if it applies to you. It had to do with cross-talk on the non-derail wires going to IN A and IN B in the 6924. I had a long run of wires from the switch to the 6924. Those wires were bundled with the power-routing wires (track power). When current began flowing through the track power wires, the board began to trigger the switch back and forth. The problem was solved by separating the power routing wires from the non-derail wires.
Here is the forum post.
