Concerning the Gemara on 13b about Ben Achya, the Gemara says that the
Kohanim who served in the Beis ha'Mikdash had chronic gastrointestinal
problems, because they ate a lot of meat.
You cited the KUNTRUS DIVREI TORAH in INSIGHTS that perhaps the meat of the Korbanos caused them stomach trouble only if they did not eat it l'Shem Shamayim, with pure intentions.
We were wondering if, according to this explanation, this was ever used against the Kohanim as a reason to invalidate them from their avodah. After all, they were there to represent the Nation in their holy service of the Beis HaMikdash. If they weren't doing the job correctly, perhaps they should have been (or were?) asked to step down from their position.
Good question. In this particular case -- eating Korbanos without the proper intention -- the Kohen was probably not asked to step down, because his only failure was to eat the meat of the Korban with the proper intentions. The fact that he became ill does not indicate that the rest of the Avodah -- the part which he did on behalf of the Jewish people -- was done with impure intentions. Furthermore, even the eating of the Korban may have been done with the intention to fulfill the Mitzvah of Hash-m, but he became sick because he also had his own personal pleasure in mind when he ate the meat. This is not reason to invalidate him from the Avodah.
We do find, however, that a certain Kohen was punished Min ha'Shamayim by being removed for doing the Avodah because of improper intentions. Yissachar Ish K'far Barka'i wore gloves when he performed the Avodah, disgracing the Kodshim. He was punished for it at the hands of Hash-m, and he was also removed from his position because of his lack of respect and his personal motives (Pesachim 57a).
However, in that case it was clear that he was performing the Avodah with improper intentions. In the case of a Kohen whose stomach becomes ill, it is not evident that he performed the Avodah with improper intentions, as mentioned above.
Another reader pointed out that perhaps, if a Kohen got a stomach ache, it was from the non-Kodesh meat that he ate in the Azarah (i.e. without wine) to accompany the Kodesh meat, since we find (see Rashi Pesachim 69b DH uv'Mu'at) that Kohanim would eat non-Kodesh meat first in order to eat the Kodesh meat "Al ha'Sova!"
Best wishes, Mordecai