Call 1-800-Comcast. Explain to the nice customer service rep (and they really are nice so please be nice to them too!) that you would like a credit because your DVR service is not operating properly as designed. You will get it (I always do).
If enough of us do this - Comcast will take notice.
The problem is clearly the guide, has been ongoing since Fall 2008, and they still seem to be dedicated to "pretending to troubleshoot" rather than repair it - perhaps a trickle of lost revenue will get Comcasts attention.