Let's say I use the pretty much disproven Techelet (Radzyner) : is my Tzitzit completely Pasul? I think according to the Arizal it isn't. Does anyone disagree?
People who participate in certain activities that are bad for society are disqualified from testifying. Also, those who've commit certain sins whose punishment is corporal, and haven't yet repented, ...
In 2002, various news sources reported that a red heifer was found and the Temple Institute in Israel declared it kosher. Many of these sources later reported that the parah aduma was disqualified ...