I'm having the same problem more or less. Monday morning around 10am the Univision channels quit working on my Spectrum-TVE and it's like the channels no longer exist for channels DVR when you try to rescan them.
I believe the problem is definitely with Univision. If you check you'll see they have a newly designed webpage for wqtching live tv and their on demand programs.
If you go to Univision.com and click the "live" tab (using chrome for me) it takes you to https://tv.univision.com/ -- but it's a blank black screen. If you then refresh the browser the proper page loads and I am able to successfully watch both live and on demand programs on their website with my Spectrum credentials. But channels DVR doesn't find Univision and it's related channels when I scan for them for the Spectrum-TVE source. (I also have HDHomerunPrime as a source and Univision through Spectrum cable still works that way.)
I think the problem we're having is when channels DVR navigates to that broken page https://tv.univision.com/ it can't find anything because the page won't load unless you manually refresh it with a browser. In other words until Univision has a link that works properly when accessed channels DVR won't find it.