X15 Rear Bank Injector Short Circuit

[Hermjeji]

Well, here we go again folks. Never a dull moment....
Time to add some details:

340,000 kms
10,000 hours

Hauling heavy at 61,000 kgs. Injector code came up as discussed when empty, took it to the place of evil due to warranty:

1. Cam lobe #4 is flaking and the associated rocker arm is damaged. They are replacing the cam and the rocker arm for sure.
2. They are checking the filter for metal and the oil cooler, potential progressive damage.
3. Still haven't found the cause of injectors.

I've read a lot on the cam wear mystery (non-mystery), and I've only had this truck for several months. At this point, i'm looking to see what else I should be looking at.

Do I go out of pocket and replace the assembly, or is the one fine If the others check out within spec?
With only one cam lobe flaking (that they could see so far) what do I guide them to look into.

Here's the cam lobe and rocker roller at cylinder 4: