“I can’t think of any perfectly off the top of my head, but they are not cases where we say “Oh he’s frum he’s probably doing something Muttar.”
Perhaps not perdectly analogous. Beitza yud zayin amud beis. the din is that if someo0ne is a meizid and does not make an eruv tavshilin, his food is muttar to eat on shabbos. someone who through “harama” (not ribui shiurim) coooked for shabbos without an eruv tavshilin, chazal assured his food. the reason. By a maized, chazal are not worried someone might learn from him that we dont require an eruv tavshilin, an onlooker will chalk it up to “he doesnt listen to chazal as it is”, while a “regular” fellow who does harama, an onlooker might make a mistake and think it is ok to do. (see rashi). So, at least in this din, chazal were concerned a person might say “he’s frum and cooked without an eruv tavshilin, must be muttar”.