Primary mirror out-of-sync (plug-mirror.rcac.purdue.edu v.s. ftp.lysator.liu.se)

TL;DR: plug-mirror.rcac.purdue.edu and ftp.lysator.liu.se are not in sync.

We've been using plug-mirror.rcac.purdue.edu as upstream and it was good, but recently users report to us about our repo is outdated, so I did some investigations:

• my server and mirror process are working well without error
• I'm in sync with plug-mirror.rcac.purdue.edu
• when trying to sync with ftp.lysator.liu.se, there are a lot of differences

I don't know which upstream is the latest, but as users report issue, I've just switched to ftp.lysator.liu.se as my upstream and re-syncing now.