Every time I start Brave it asks to set as the default browser, however when I accept it seems to not change my default browser settings and shows the same message the next startup. It does not display any messages or bring me anywhere upon the button. I have looked at similar reports and they are either not on the dev build or showing very different behavior.
Brave Version 0.56.2 Chromium: 70.0.3538.35 (Official Build) dev (64-bit)
Also installed on system: Chromium, Firefox & Opera