Recent Posts links don’t work as expected

My recent posts widget creates urls with the post name in, but when I click on them, I get the correct url in the address bar, but on the page, I just get all the posts in date order.
For example, if I click on “DIY Bird Box”, the page opens with “http://www.foundfood.com/%20/bird-box/” in the address bar, but the first visible post is “Turkey Tail Fungus” and my selected post is the fifth one down.

Any ideas what could be causing this and how to fix it please?

The site is: http://www.foundfood.com
the Theme is RCG Forest.
and everything is up to date.