I’ve been having the same issue, been playing around with xteve and finally got the DVR added to Plex. I’m begining to think it has something todo with the HDHomerun itself. I unplugged the HDHomerun Extend. Then killed the server and xteve. Then ran xteve, then plex and set it up. Once I got it added I then plugged in the HDHomerun and so far things have been going ok.
So far I ended up having Plex supply program data and used a cable provider in the area so I’m playing with channel mappings right now. I haven’t tried having xteve use the XMLTV data yet I just wanted to see if I can get it to work before puting more time into it.
Hope it helps!