I have not heard of these specifically, but if it's indicating these sensors are missing (hence the reboot), and based on the history of this device I would suspect VERY strongly that these sensors are all in the Display. Apple's naming conventions for these sensors are not made public, but they tend to use a pretty normal set of abbreviations. And this would make sense to me (D at the end for Display).
I don't have much in the way of technical documentation for these specific units, but my suspicion is that whatever line the data from sensors is coming in on is the issue. Could be the FPC, or the the replacement cable. Make sure all your solder joints on the FPC are sound. Check Diode mode readings for whatever connector was replaced. You can find expected readings at https://logi.wiki/index.php/iPad_Diode_M...
Any suggestions? Ideas?