After 12 hours of being shutoff, I must reboot my X1 DVR to watch tv. Otherwise when I use my X15 remote to try and turn the tv and DVR on, only the tv turns on. The tv screen remains black as if the X1 DVR is not on but the light on the DVR is on.
There are some other messages here about similar problems with certain TVs. It is likely an HDMI handshake issue and could be related to a bad cable or the time it takes one of the devices to wake up from sleep mode and be ready. If simply unplugging and replugging the HDMI cable wakes it up, that is probably the issue. Some people have found turning off the low power/sleep mode of one or the other devices helps, some fixed it with a new cable, and some swapped their X1 box.