The intro to the chapter in the Artscroll states that if a Kohen is Rabbinically disqualified from the altar but performs the avodah anyway, he is not subject to lashes.
1) Why is he not subject to Rabbinic lashes?
2) What is the methodology that decides if Rabbinic lashes are given or not given for a Rabbinic violation?
Barry Epstein, Dallas, TX
The Rabinic prohibitions are because of Mar'is Ayin (see Rambam Hilchos Bi'as Mikdash 6:6). The Rambam does not mention that he receives Makas Mardus (Rabinic lashes), merely saying that "he does not receive Malkos and his Avodah is Kosher," implying that he does not receive Rabinic lashes as well (as sometimes the Rambam will note that one receives Makas Mardus). The guidelines for Makos Mardus are quite complex, and there are many different opinions regarding in which cases they are given. In general, it seems that Beis Din is able to give Malkos when they see someone has transgressed a prohibition which he might transgress further in the future, or has committed a transgression which others would similarly commit unless an example is made out of the sinner. It is possible that, especially when the prohibition is one of Mar'is Ayin, which is not of a very severe nature, if there is little assumption that the person would do so again or lead many others to follow his example, Beis Din would not give Makas Mardus. This could be the reason that a Kohen who would have one of these Mumim would not receive Makas Mardus.
All the best,