QC 0.6 broke a lot of plugins
I only use this QC site for specific people and always want it locked down, so with 0.52 I always used the wordpress plugin Force-User-Login. Worked excellent until I upgraded to 0.6. Now I get "too many redirects" error and cannot login. So I removed that plugin. I suspect there is something under the hood of QC that has changed and is a bit quirky.
I wish the QC changelog would cover every little change. What other things were changed? For instance, what does "themed login pages" refer to?