Rice Pudding
I think you will find it doesn’t matter one little bit whether they are a JFO or FO who is RP or RPIC, if he or she is PF they log P1 and in the “Holder’s Operating Capacity” they log P1US. RPIC can be placed in the remarks column if you so wish. Page “V” part “9” of your HKCAD logbook explains it fairly clearly.
I have known about this change coming for about a month now. It is more a case of limited sectors and resources and trying to expand the airline than anything else, i.e. not wasting resources. I find it very hard to believe that Korean Airlines mistook P1US as P1 in the relevant FO’s log book if it was filled out correctly.