OS detection through JavaScript increases fingerprinting possibility
With JavaScript enabled, https://coveryourtracks.eff.org/ is capable of detecting that the actual OS is not Windows (as the User-Agent string suggest). It detects correctly that:
Platform Linux x86_64
Compared to a case when really using Windows, this is another possibility to fingerprint the browser better.
Possible solution (not tested personally):
https://pastebin.com/raw/wR6k1GvD (from a comment in the link above)