I have seen this issue be a problem with the power coming from the driver board also. Just recently on a no fear I was working on. Changed out the driver board and problem went away.
I have not had a chance to do bench work on this driver yet.
Being all flippers you need to check this power.
Assuming it’s not the cranks because it’s all 3.
Sometimes it’s the cabinet flipper optos, but again on all 3?
Yeah, might be something in the fliptronic. Need to check there also