Some hints from our headquarter as below:
concerning the problem with the rejected BNs it looks like that there was a timing problem.
the SEP board was not able to make the necessary calculation in the correct time.
As a first Step I recommend to format the SEP board . if this does not help please try to exchange the board.
but the problem is not that easy It can also be the case that Backplane, Sensor, MAT or CAN bus are also involved in this problem.
but the quickest and easiest solution is to format the SEP
So that why I recommend you prepare a good C4 for test, to confirm that no any mechanical such as gear or toothed belt...etc
On the other idea, may two or three part were problem at same time.