James,
If you’ve witnessed the gate and lock fault tripping the car up, clear that issue up and then watch. There are a number of faults generated at a shutdown that have to do with the initial fault, then recovery, but not necessarily back to automatic. Door lock opened in flight is error 43, but you’ll also flag an 18, 58 and 94 (typically anyway).

Be sure the tape guides are in good shape. (Also in the manual there is a specific voltage value to read at DPP+ and - if I remember correctly).

Those DPP sensors ride pretty close to the face of the perforated tape, so take a peek at those.
You can also bump up your inspection speed, and while on cartop inspection, open the selector box and move the box and tape around while watching the two green LED’s for proper toggling on and off.

Do you have the RVU box where you can set the fault trap and review it later? It’s a tremendous help.