Update after Johnny's post.....
01/27/2021 We turned the power on to number 2 but left CPU card off and on inspect. Car 3 did not fault out at all.

02/03/2021 turned CPU card on for car number 2 and left on inspect. Car 3 faulted out 02/08/2021 with Fault 7.

Thinking out loud, but that seems to eliminate encoder noise, as car 2 was not moving at all.