Comedy Central's South Park, s22e06 "Time to Get Cereal" is NOT available on demand.
This episode is, however, available on the Xfinity Stream platform.
I reported this issue 2 weeks ago and it still hasn't been fixed. Additionally, episodes 8, 9, and 10 are NOT available on demand either. All these episodes are available on the Xfinity Stream platform, so there's no reason why they shouldn't be on demand.
Tcalg -- Thank you for using the Xfinity Forums for your concern and I would like to look into this for you. Are you still seeing these missing?
The remaining episodes of season 22 of South Park expired from Xfinity On Demand on February 10th. For the record, the episodes I reported never did appear on demand.