Subdomain Permalinks Changed – Now Posts Are 404 Pages

Yesterday sometime, the all of the permalinks on my sub-blogs changed from year/month/title to year/month/day/title.

When you click on the links to any of the posts, you get 404 pages. I can fix this by going into each site and changing the permalinks back, but I’ve got hundreds of sites.

.htaccss and wp-config weren’t being tinkered with. My host has scanned for malicious code and found none.

I did update some plugins, but then deactivated them to see if they caused this.

Any thoughts? And, is there a way to define sub-blog permalinks in htaccess to fix this permanently?

I’m on 3.0.5 MS with subdomains.

Thanks!