Channel has no buffer, won't record

I have two Roamios and subscribe to Comcast Xfinity in Atlanta. Starz Edge, channel 711, started acting strange about a week ago. It no longer buffers the program. That channel will pause, but won't rewind, fast forward or record. As far as I know, this is the only channel affected and the problem is on both my Tivos. Anyone have an idea what's the cause?