CMS pages (such as about-us, privacy-policy etc) link fine from root domain (such as domain.co.uk) and from domain.co.uk/category1.html. In this instance then the correct URL is domain.co.uk/about-us and the about-us page is displayed.
However when navigating to CMS pages from 2nd level category URL's (domain.co.uk/category1/category2.html), the link is domain.co.uk/category1/category2/about-us, and this generates a 404 page as the page doesn't exist.
What is the solution to this?
I'm using Magento 2.1.5.