As noted in the title, it was expected that any verbose output from the request (including DoH) would go to the same debug function instead of being dumped into the default destination (stderr) so that all of the output can be properly redirected.

example patch commit: bidstack-group@125c1a8
this is probably not the complete fix though, as I see there's also CURLOPT_STDERR which isn't copied over to the DoH request as well (and possibly other things)