Google's John Mueller said it is fine using either root relative links (/google.html) vs relative links (google.html) as long as you are consistent on how you do your URL rewrites, Google can figure it out. Problems can arise when you provide mixed signals to Google and Google gets confused about the direction you are looking to go.
John Mueller said on Twitter "Usually the problems come from sites that do inconsistent URL rewriting (eg "create" subdirectories). If a site has a clean setup, relative links are totally fine."
Here are those tweets:
Forum discussion at Twitter.
To comment, click here.