AFAIK Charter do not block ports http://www.gnutellaforums.com/showth...t=33712&page=4 what they do is shape the p2p use of heavy users. They choose them as they become noticeable as heavy users of bandwidth. It comes under their fair use policy.

Perhaps you may have come under such notice & they shaped you just temporarily. Perhaps as a warning. With their devices they can not only shape the p2p bandwidth, but they can also block your p2p programs from connecting if they choose to do so. They can apply it to specific programs or inclusively. I guess depending upon p2p protocol, ports, etc.