Firstly, LOVE the new grid view for Program Guide. When I select HD Channels Only though, if there is a matching SD channel this too gets displayed (e.g. both SD BBC1 & HD BBC1 are listed here in the UK) which seems a little odd, I’d expect only the HD channel to be listed.
I’m state side.
However, I would expect the full lineup of channels to appear in the guide and in my case it does (SD and HD channels).
For me the problem is that when I select an HD channel from the grid guide view on Plex Media Server Web interface the channel is changed to the analogous corresponding SD channel.
So for example, selecting CBS (HD) channel 602 results in CBS (SD) channel 002 being tuned. Same is true of all other HD channels tested.
However, switching the guide from “Channels” to “Discover” and repeating the channel tuning (assuming an HD channel can be found in the guide) will result in tuning of the proper HD channel,…
Edit:
Is that the behavior you were seeing,…???
I’m having the same problem. when i tune to the HD channel 502 - CBSHD, it tunes to 002 CBS standard definition. i turned off the sd channels in tuner settings in plex, but it results in the HD channel being turned off.
have you been able to have your problem resolved?
No the problem has not been corrected and your attempted work around is one of the few solutions I thought might work.
Also note that the new Windows Plex Player has had an update to support the new grid guide and it has the bug. So now this known issue is spreading to other Plex apps unpatched.
As I stated before if you switch from “Channels” to “Discover” it should tune to the correct HD channel for the given HD channels you can find (but then you lose the new grid guide). Also, all scheduled recordings should work properly overall if channel number is specified.
Hopefully a fix will become available soon.
It’s not “spreading” to other apps. Plex Media Player in desktop mode uses the exact same app as loading in the browser (but with better codec support, thanks to the player). Once this is fixed in the web app, PMP will just need an update to take advantage of it too. 
I am now having the inverse problem in that I don’t see any SD channels but require them as the local new on the BBC is only on SD. SD are no longer showing anywhere.
