What does mrc3b pp rp on erb mean?

I can't speak to all the codes and jargon, but Medical Readiness Category (MRC) 3 means you're non-deployable. If you have a 3 anywhere in your PULHES, you will probably have to go through a medboard process.

To use me as an example, I have sleep apnea and require the use of a CPAP machine. My PULHES is 212111 because it doesn't hinder my MOS, so I didn't have to go through a medboard. Also, I have a no running profile, but again, no hinderence to my MOS, no medboard. However, I am MRC3 because I can't take the the CPAP machine downrange to certain areas, making me non-deployable.

I re-enlisted INDEF right before the rules changed last year, so I was grandfathered in, but if you plan to re-enlist, you need to talk to your doctor about getting that downgraded.