I found this one about Time Warner / Charter / Spectrum a month ago when I was visiting my family: they are traffic shaping on the port that Plex uses (32400). I couldn't reliably stream video from my own server to my tablet at either my brother's house (Comcast) or my parents' house (Frontier) until I opened a VPN connection to my home and then it worked perfectly.
I have a problem with this - what do they care what I'm using the upload for, as long as it's legal? Now I'll just be sure to put everything through a VPN when I need to interact with systems I have at my house, and they can just see a whole lot of TCP 443. Douchebags.