Why are block settings lost after Drupal upgrade?

This is a new one for me. I upgraded a Drupal site from 6.20 to 6.22. After the core upgrade, the block visibility settings are all goofed up. Quite a few that were enabled prior to the upgrade are now disabled. Additionally, the "Page specific visibility settings" are missing for those blocks.

One other clue in this mystery is that, on the main block admin page (/admin/build/block), my three active themes are in a different order. I'm not sure whether that's related, but I've never seen it before.

I do upgrades on a staging server, so my production site is still intact. For now, I'm going to restore the blocks, comparing the prod with staging settings. I'll see if that restores it to fully functional. Regardless, it makes me n开发者_JAVA技巧ervous. I saw no errors or warning during upgrade.

FYI, my general order for doing the upgrade was:

1. Empty staging site files and dbase.
2. Take production site offline.
3. Copy entire prod site to staging.
4. Dump prod dbase, restore to staging dbase.
5. Disable all non-core modules. Switch to core theme (Garland).
6. Upload and expand drupal-6.22.
7. Move 'sites' directory from old to new.
8. Run /update.php.
9. Enable necessary non-core modules.
10. Run /update.php.
11. Switch back to custom theme.

Bam, lots of blocks disabled.

This is a bug. See http://drupal.org/node/1173012