“. . . Eating teruma is different, because it is called Avodah, and Avodah of the son of a divorcee or a Chalutza is valid after the fact.
As per the Mishna: If a Kohen sacrificing Korbanos, and it became known that he was the son of a divorcee or the son of a Chalutza, all the Korbanos that he sacrificed until then are disqualified. And Rabbi Yehoshua validates them.”
And we said: What is Rabi Yehoshua’s source? ברך ה’ חילו ופעל ידיו תרצה מחץ מתנים קמיו ומשנאיו מן יקומון
. . .
Once Someone known as a Kohen accepted 5 Shekalim for Pidyon Ha`Ben.
Unfortunately it was discovered that he was the son of a divorcee and not fit to accept such.
The question was asked, does he need to return the money and does the father need to do Pidyon again?
There were those who quoted our Gemorah, saying that since at the time it was unknown that he was the son of a divorcee the Pidyon was valid.
However Le`Halacha we hold that only his Avodah is valid, but anything he accepted on the basis of being a Kohen must be returned.
This is clearly indicated in the Gemorah, “. . . Eating Terumah is called Avodah . . .”.
The Author made use of the Sefer Chashukei Chemed when preparing this Torah.