Honestly Comcast said it was by one of their partners. Probably a construction accident.
Cable companies are lazy as fuck and NEVER bury their lines to the depth they are supposed to. Many many times they are barely a foot deep. Very easy to cut one doing even minimal construction work.
is it possible weird activity and intentional? sure
But I would error on the side of caution until further information comes out. In all likely hood its just an accident.