Depending on how they do their web streams, it could be that whatever software they use either doesn't have a new template with the new look, or the person who initiated the steam, often a web producer (not a technical director), forgot (or didn't really notice or care) to put up the new look. Stations sometimes "recreate" their on-air look with the built in basic graphics system of whatever streaming software they are using. They aren't actually using an output from a "real" broadcast graphics system for the web stream.
FOX did for three years before giving up in 2009. Its been a syndication service longer than an original program-type network. I say get rid of MNT already and have those stations finally become Independent again.