Sidekiq is where you find all the background jobs that work their magic backstage. They normally all work on a schedule, but can be hurried-up by triggering them manually.
If you add /sidekiq/scheduler to the end of your site address (ie [YourSite]/sidekiq/scheduler) you should see a list of all the scheduled jobs.
There’s one in there called Jobs::EnsureDbConsistency which you can run early to speed up the changes to your default group names.
Instead of scrolling down looking for it, you can also use Ctrl+F or ‘Find in page’, etc and search for something like ‘ensure’ to find it quicker (I think there are only two jobs with ensure in, so it narrows it down a fair bit 
)