I think that must just be coincidence.  Edge fails about as much as Brave for me at the moment.
I think the DNS thing is probably a red herring also.  DNS wouldn't come into play once the hostname is already resolved.  It would be cached for a while too.  I'm not having DNS failures anyway.  I'm having failures where the page doesn't respond and fails to load right after it loaded a moment ago (proving DNS resolution was successful).
I suppose there could be some kind of crazy AJAX stuff on the promotions page that relies on a separate DNS mechanism.  That would sure be odd, though I guess stranger things have happened.