Malcolm Butler just wants to be a starting cornerback for the Patriots, plain and simple, but sometimes things happen. In this case, what happened is a cancelled flight due to weather and a cornerback showing up a day late for voluntary team OTA's.
Butler, the hero of Super Bowl XLIX, attempted to fly to Boston for OTA's but was delayed due to weather. The Patriots were not happy with this and decided to keep him on the sidelines for the first couple weeks of practice. The problem with the punishment is OTA's are considered voluntary, so Butler had the option to not attend.
According to the CBA, the Patriots are in violation of the rules for punishing a player for a voluntary event. Butler did not want to go forward with the grievance, but the NFLPA insisted because it is such a blatant violation of the CBA. Butler reportedly was in the starting left corner position upon his return to practice and he looked very good.
Unlike the other case the Patriots and the NFLPA are dealing with, this one should be resolved quickly without much pain. The Patriots made a mistake, Butler might want to leave a day sooner, and that is pretty much it.