Popa, well, theoretically if there was a mentor and every one of his gerim was filmed eating a cheeseburger at McDonalds the day after the conversion, then a beis din would stop taking gerim mentored by that mentor seriously. But of course nobody’s that bad. I think every beis din should consider each ger on a case by case basis. I suppose they could keep in mind the history of the mentor if in the unlikely event they have reliable information (not just rumors) about the gerim he’s mentored. Retroactive invalidation of all a mentor’s gerim should never occur. Individual gerim should never be “invalidated” unless it’s 100% clear they were flagrantly and publicly violating mitzvos (as generally practiced in their Orthodox community) immediately after conversion.
Aurora’s right. This kind of thread doesn’t belong in the CR. Who gave anonymous internet commenters the right to be armchair poskim trying making the world more difficult for gerim (who already have it hard enough as it is)? We should be very careful about the mitzvah not to oppress a ger, because gerim are more sensitive and often have difficult experiences in offline life as well.