Thank you dare2be for pointing out that I can review the state of past recordings. In this case however, I must admit to cockpit error. The show did not record because HBO did not broadcast it.
I still agree with previous comments about the DVR's unreliable scheduling and performance. I had mysterious recording failures in the past but I attributed them a new contractor providing the guide listing. When that happened, I deleted all my timers and installed new ones. This seemed to stop missed programs as long as the guide did not change the program's title (or some other internal information) from what the timers used to recognize a program.
I still agree with previous comments about the DVR's unreliable scheduling and performance. I had mysterious recording failures in the past but I attributed them a new contractor providing the guide listing. When that happened, I deleted all my timers and installed new ones. This seemed to stop missed programs as long as the guide did not change the program's title (or some other internal information) from what the timers used to recognize a program.