Aegir views go missing after clearing all caches

After successfully applying HTTPS to my various sites, I thought I'd try also applying it to Aegir itself. First I enabled encryption and that verified OK, then I required encryption. I had to log back in, but no content was being displayed in any Aegir tab. See the attached screenshot for the Sites listing page.

Clearing all caches didn't resolve the issue.

When I dropped back to Bartik theme all the content was there. Switching to Eldir again and the content returned.

Not sure why yet, but at least it's working now.

Workaround

Whenever this issue presents itself, it can be fixed by rebuilding the registry on the hostmaster site, the Aegir site itself.

drush @hm rr