I've noticed that unless TVE is prioritized over the other tuners, then TVE will be the main source of watching. I had my Primes prioritized over TVE and the TVE channels would be hidden automatically. Usually tuner sharing would kick in if more than one device was watching the same channel. It was my understanding though if all of my tuners were being used, TVE would be used to record if there was a scheduled recording. Eventually I just took TVE out of my lineup because the stream qualities were so bad. It's a cool concept but the cable companies really dial down the quality of the streams.
Yeah, it is set to show all channels.
one other thing Channels combines HDHomeRun channels and TVE ... So if your HDHomerun tuner is above TVE in the settings of your FireTV you will only see the HDHomeRun Channels numbers. I wish there was an option to not combine channels.
"Explain it like I am Five" is a known expression. It is a bit sarcastic, but generally means give me the simplest answer. It can also be used in a derogatory manner to insinuate that someone said something that didn't make any sense.
It was not meant to be literal...which might be odd coming from me, who takes almost everything literally. 
That is what I was hoping for, that it was an option.
Devs, can this be an option? It is not the end of the world if it is not, or if it requires a bunch of hoop jumping. Like I said, it is rare for me, but may not be so rare for others.
I understood the five comment ... I am into computer support so when a client has a problem ... I try to explain it as easily as I can and not assume they have the technical knowledge at first.
The simple explanation is that channels are combined on the guide, and tried in the order of priority as listed in the settings area of the app. So in this case it tried the hdhomerun first which has no timers available. Then it tried TVE, but the NBCSN TVE feed is not working reliably either.
What happens if the Channels on TVE and Cable show the exact same show but are not combined which a lot are not for what ever reason ... in that case will it still fall over to the TVE channels .... I would think not.
Th logic for combining tuners appears to be off.
I believe the merge is based upon the call sign. For instance, TVE NBC and Fox get merged (KNBC and KTTV for me), while ABC doesn't, because its call sign for the guide is ABCSTR, not KABC.
I see that now thanks for clearing it up wish there was a way to edit the TVE call sign.
These are a few not combined and have the same listings
XFINITY
AMC 771 6086
IFC 781 6088
WETV 780 6089
Okay, so it should have just defaulted over to TVE, if that channel was working right,.
Okay, that is simple enough.
So, that is the way it should whether I am recording something or trying to watch live?
Thanks.
Recordings follow the priorities set on the DVR (and viewable in the web interface). When watching live on a client, the priorities may be different than what is set on the server. This is something they are working on, to synchronize these kind of settings between server and the client. But it’s not ready yet.
Not keen on this 'Explain it like I'm five' mentality. 'Listen, read and operate like you're an adult.' ...is my advise to anyone in your situation.
Well, someone clearly woke up in charge of the world this morning.
Refreshed and ready. I owe you an apology, I shouldn't have assumed you're a functioning adult. Please forgive me.
No problem, no greater effort was expected of you.
BTW, I'm just ribbing with you...if the title truly bothers you, I really have no issue changing it. It was only in the title, not the question.
I'm just ribbing with you also. My people will give as much warning as possible before I take over fully.
I do appreciate the heads up, and I changed the title, anyway. 
"explain like im five" um....u realize that 5yr old these days use an iPad and other techy things with ease pretty much. Gen Z is the internet generation, and They know the tech better than most us older generation at such a young age.
So with out the context of the age/generation of the person using that statement, it is impossible to really respond.
For me, being a tech person for 25yrs+, having to "dumb it down" so, that tech illiterate and especially most senior citizens can understand things...frequent but often difficult thing these days. My Grandparents have gotten so bad, that even that, tell them like they are 5yrs old, does not work and it is still too confusing/overwhelming for them...but with the onset of dementia and Alzheimer's....that makes things much harder.