CMS Collections menu links broken

Hi need help with a two link issues not sure where to begin. When on a collection item page whether e-commerce or cms the menu links break. What happens with the url is strange

for ex

regular url

when trying to navigate the website using the menu, ex going back to shop page, the links break and show something like this instead

this leads me to the 404 page any help on this would be useful thanks guys

Here is my public share link: [LINK][1]