The same thing happened here. I watched episode 6 the other day, and 7-10 were there. Went to watch them tonight and 7-10 are gone. Very frustrating.
We noticed the same thing this week. Episodes 7-10 just disappeared. I called Comcast and they agreed there are 10 episodes aftet I pointed out that Amazon Prime has all ten episodes. Their response is that Paramount controls access and Xfinity has not control over what is provided. That does not make a lot of sense. The Paramount website shows all 10 episodes. Like Xfinity, Spectrum website also shows only 6 episodes. I am guessing some sort of contractual dispute between the cable providers and Paramount.