Recorded SD and not HD

For some reason the DVR (Mac mini) using an HDHomeRun Prime recorded the Indy 500 in SD today. I selected to record the event using the Apple TV guide on channel 232 (HD) and it recorded on channel 4 (SD). I have all the SD channels blocked in the settings for the tuner.

I've never had this happen before. Any idea why? I'd like to prevent this from happening again.

Thanks!

May have found the issue. While the SD channels are blocked in the Apple TV app, they are not blocked in the DVR web interface. I guess these settings are not shared?

Correct. Client and DVR channel preferences are separate.