Zypper dup preliminary download significant slow down

After zypper dup start it downloads at 40-50 MiB/sec, however at the end speed goes down to 200-300 KiB/sec and even less:

Seems old bug with cdns/mirrors? Where to report the bug?

@akontsevich Did you not see https://forums.opensuse.org/t/heads-up-large-snapshot-coming-please-let-the-mirrors-sync-before-upgrading/195177?

No, but it started few weeks ago, not today.

Then likely a locale issue and mirror locations.