Hi there, @evanelias 
Welcome to the Netlify Forums 
this is a great question.
When folks create their first site on Netlify and we run the first build, we set a version for all of the major languages that match the default version installed on the build image at the time. This is then stored on the site’s repo object.
I believe that if you re-connect your repo, it will reset the versions for you. In order to try this, you can follow these steps:
For your selected site, go to Site settings > Build & deploy > Build settings , select Link to a different repository , and then select the same repository to re-link your site to it.
Let me know if this works!