Processes will not start in same region

Hi there – I’m trying to spin up an app that should, as far as I can tell, start in just one region (syd). But whenever I deploy, one of the processes is always spun up in a completely different region that I don’t seem to be able to control.
I have these two processes:

[processes]
  rails = "bundle exec rails s -p 8080"
  sidekiq = "bundle exec sidekiq"

And I’ve run this command:

$ fly regions set syd --group sidekiq,rails

I’ve also tried modifying memory and similar, but it doesn’t seem to make a difference, no matter what I do sidekiq shows up in a random region. Since I have the redis server it’s meant to talk to also in syd, redis is complaining.

Any idea how I can definitely spin up the sidekiq process in the right region?