RSS feeds not working with Yoast enabled

I’m guessing that there’s no way to remove / disable the RSS element from Yoast (I know there was a setting to fix a video/podcast issue in a previous version) but I’m at a loss to know what’s happening.

Simply, when Yoast is active, my RSS feeds don’t work.

I have been troubleshooting but getting few clues – simply, I have Yoast as the only plugin that’s active and they fail, while with everything on and Yoast disabled, they work fine.

This is I think in some way related to the permalinks. I’ll also say that I had been attempting to get a plugin called GN Publisher working, and at some point I disabled Yoast, and it was when I reactivated it that I noticed the problem (as I was working with GN’s RSS feeds, though I can’t say for sure when the problem began – but on or off, it makes no difference)

With Yoast ON: you’d think the site RSS would be?https://www.isthismusic.com/feed/ but that doesn’t work. (reverts to the main page, redirecting to whatever the URL would be without the feed details). However, https://www.isthismusic.com/features/feed/ works ok (the RSS it generates is around a megabyte in size by the way)

(extra info: https://www.isthismusic.com/feed/gn does work)

With Yoast OFF: 

https://www.isthismusic.com/feed is fine (I say fine, it works and seems to have the correct articles etc listed)

https://www.isthismusic.com/category/features/feed works ok, a fairly normal 60K RSS. (Permalink structure is /%postname% – which is also confusing)

(extra info: https://www.isthismusic.com/features/feed – well, it works but only delivers headers, no articles.)

Thanks in advance for any advice….

The page I need help with: [log in to see the link]