That was the info I had found, the plungers need to be keyed to the piston bore to prevent the assembly from turning and the roller ending up 90 degrees from where it should be.Read a report that there was a coating change in the roller. Doubt that is very significant as the main issue is the roller turning on the cam with no reasonable way to stop that.
For some reason, while other engines had issues with the CP4, the number of troubles with the Ecodiesel has not been of major significance.
Bio,I don't know if this is fact or not, but this was posted in the 3rd gen EcoDiesel Facebook page:
"I did some research on what change was made in 2020. The only change for the internal design of the Bosch CP4.2 HPFP was a symmetrical cam profile. The CP4.2 up to Dec 2019 had an asymmetrical cam profile, meaning the lift slope was different than the drop slope. I’m uncertain how they figure this will make any difference. The electric low pressure lift pump at the fuel tank is the one major preventative components. Air of any amount getting into the CP4 pumps was identified as a major cause of failure along with not enough fuel lubricant in ULSD. Priming the fuel system multiple times after a fuel filter change is very important to prevent air getting into the CP4."