It looks like the configuration is always re-applied.

How to simulate it:
1 - start a queue with the state paused.

  Sidequest.start({
    queues: [
      { name: 'high', concurrency: 20, state: 'paused' }
    ]
  })

2 - go to the dashboard an try to activate, the status changes to active.
3 - when sidequest try to process a job, it calls the grantQueueConfig. Which is checking and enforcing the config set on start, check here.

It prints the log:

[warn] [2025-07-18 10:08:56] [pid:1281050] [Sidequest] [Engine] : Queue config for high exists but differs from the provided configuration. Updating...