You seem to have a couple things going on here (and a couple different programs) ..
The PVR addon seems OK, the "failed to deliver" messages come up when Kodi doesn't have an EPG entry for a channel. This happens a lot when channels are added/removed. The fix for this is pretty easy, go into PVR & Live TV Settings, and choose "Clear Data". This wipes out all the channels, EPG, etc. and reloads it. The EPG data is cached these days so the reload should only take a short amount of time. That should resolve that.
The other problem you're having is with the official HDHomeRun script application. I don't have that installed, but I can have a look later to see if I can help out SD. It's open source now so we can contribute fixes. Would have to duplicate it, of course. I'm not sure where the discussion forum for the app went, but you could ask in the root of the "HDHomeRun Software Setup" forum if this is something they know about.
With that said™ ... you don't need to have both programs installed if you don't want to. The PVR addon integrates into Kodi so you can use the EPG, Timers, Recorded TV, etc. with the native Kodi interface. The HDHomeRun View program is a standalone application that looks and feels like the native HDHomeRun app. One program doesn't need the other to function. There is no problem with having them both, just wanted to point out that you don't NEED to have them both. Whichever one works the best for you!
I seem to be coming up on a lot of free time due to forced telework, I have no problem installing the HDHomeRun View app and see if I get the same thing. If so, happy to help you and SD work it out if I can!
edit: If the built-in Kodi stuff (Channels, Guide, Recordings) aren't working with the PVR installed please do let me know. That would be something likely to be my fault
