I'm having the same problem with xfinitystream - Outlander s01e01 is playable, the only other episode listed is s03e05, but there is no "play" button displayed. Ray Donovan has one episode listed, s05e01, and some other shows I searched for are entirely missing: Game of Thrones, Room 104. Something is definitely going wrong at Xfinity. They're probably upgrading something again.
Well, the Outlander episodes were there for a few days earlier this week, now they're gone again, except for s01e01. Game of Thrones is completely missing, as is Room 104, Ray Donovan only has s05e01. Almost as if they wiped the server, and now have to completely re-populate it. Very annoying.
Update: Well, silly me, those episodes are gone because my subscriptions to those channels mysteriously disappeared. The channels work fine on my TV (tivo with cable card), but are completely missing on the tv.xfinity.com channel listing, and also the andriod Stream TV app. I guess they goofed up a billing code somewhere.