I'm in Wisconsin which has been a Charter market from the begining. I am able to record and view all channels that I subscribe to including premium channels such as HBO, Showtime, etc. I have a HDHomerun with the cable card and it works just fine with DVR for me. I don't know if this is relavent to DRM or not, but Clear QAM is not in my area, only QAM hence the cable card.
I found this link which explains DRM and QAM differences:
https://getchannels.com/faq/#what-is-the-difference-between-encrypted-channels-and-drm-channels