for example:
https://www.parabola.nu/mirrors/cyberbits.asia/

it is currently the only such example; so this is still a hunch - however, i noticed a similar problem recently with yandex - they apparently had two separate replicas, one for IPv4 and one for IPv6 - parabolaweb only checks via IPv4 and it reported the mirror as out-of-sync - the IPv6 replica was up-to-date; but the IPv4 replica was not synch-ing - even their admin was confused at first, until i discovered the discrepancy between them