Today it gave me : rsync://mirror.cambrium.nl/gentoo/ and http://mirror.cambrium.nl/pub/os/linux/gentoo/ Reproducible: Always
Which mirrorselect options did you use? I'm asking since the --rsync seems to control where the input URLs come from. Looking at mirrorselect's get_filesystem_mirrors function, it looks like on or more URLs might be coming directly from either the SYNC or GENTOO_MIRRORS variables in /etc/make.conf.
I use "mirrorselect -s 4" - mostly I use "-h" too, but here not.