Permalink badness

There is a page on my site that I’ve discovered is not working properly, and I believe it is a permalink problem.

I have a series of pages on my site that are grouped under a page called “Radio”. The sub pages load just fine; but trying to go to that main page (which is in a series of links at the top of the site), causes a series of redirects that eventually cause the browser to give up.

Here is the site:

https://greatgreatjoy.com

At the top is a page link called “Radio”. If you click on that link, it displays first

https://greatgreatjoy.com/radio

in the address bar, and then changes to:

https://greatgreatjoy.com/sources

then back to the first one, then back to sources, and so on.

It did work once. If I change the permalink in the page editor to something else (like “radio2”) it works. But won’t that mess up how the page is indexed on search engines? How can I resolve this?

Thanks in advance.