Steps to replicate the issue (include links if applicable):

• Have a page in a valid non-category namespace (e.g. zhwiki:Wikipedia:裸網址)
• Create a page with that page in language variants as a category (e.g. [[Category:Wikipedia:裸网址]] in my sandbox on zhwiki)
• Check the category bar of the page created.

What happens?:

A blue link to that non-category page was generated in the category bar.

What should have happened instead?:

This bad category should be a red link to the category namespace.

Software version (skip for WMF-hosted wikis like Wikipedia):

Other information (browser name/version, screenshots, etc.):

While working on T328477, I noticed this issue. This is not a valid use case, but we should avoid this confusing behaviour.
And the findVariantLink() function was used in more important places.