Hi @VineetPandey
I too tested your scenario in 6.5 it works even though its null selector whereas in 6.5.9 it is considering the entire url as suffix and throwing a malformed url exception.
G Resource Path Info: SlingRequestPathInfo: path='/libs/cq/gui/content/editor', selectorString='null', extension='html', suffix='/content/we-retail/language-masters/en..html'