Does it show up before (or during) a commercial break?
6 dots allows for 64 possible characters, or 36 Alpha and Numeric characters and 28 commands, or 52 upper- and lower-case Alpha characters, ten Numeric characters, and two commands. I count 16 distinct codes between the 3F blocks at the start and the end.
However, the dot pattern is the same between the two examples posted, which seems to eliminate a message addressed to play different Ads stored on the Local Receiver.
So, it's not just Dish. Has this same behavior been reported on DirecTV or a different cable provider?
I haven't not seen anything like this on our 4K Joey or Hopper 3, but then we may not be watching the right channels.