404 errors as a result of Sermon Speaker page

Sermon Speaker 5.9.2
Joomla 3.9.16
www.the-rock.org.uk

I have checked my access logs on my server and can see multiple 404 errors when the following page is visited:

www.the-rock.org.uk/media-pages/listen-to-sermons

When on this page and click on any other item from the top menu, for example, "In The Community" you are forwarded to a 404 like this one:

www.the-rock.org.uk/the-rock.org.uk/in-the-community

This issue happens only if you visit the Media Pages -> Listen to sermons first.

Can anyone shed any light on this?

Hmm, strange. When I started looking at this, I could reproduce it.
Now while writing this post, the behavior fixed itself.

Now I don't know. Did you fix it right now while I was looking at it?

No I didn’t Thomas.

The exact thing you are experiencing keeps happening with me. It breaks, then after a while ‘magically my fixes itself.

I am at a loss. Just doesn’t make sense!!??!!??

Quite sure, that isn't coming from SermonSpeaker itself. The menu on top is a completely different module with a different component behind it.
I'd also say this doesn't come from Joomla core.

I would first check if you have 3rd party software related to menus or caching which could cause such issues.
To me it looks like something sets a base path for the link creation which for some reason doubles the domain in the URL.