found the answer:

Will Flic work when the Flic app is running in the background or when the app is closed?
Your Flic works together with the Flic app like this:

Flic app is running and is in the foreground: All Flic actions can be triggered.
Flic app is running in the background and the device is unlocked: All Flic actions can be triggered. On iOS, some actions may require you to tap a notification first.
Flic app is running in the background and the device is locked: The huge majority of Flic actions can be triggered. Some actions can be limited by the platform or by the operating system. On iOS, some actions may require you to tap a notification first.
Flic app is closed (you have manually closed the app):
For iOS, Flic actions cannot be triggered.
For Andriod, The huge majority of Flic actions can be triggered. Some actions can be limited by the platform or by the operating system.

I have a Flic button on my car steering wheel, programmed to do Next Track on my iPhone.
However, in the morning, when i first get into the car, the button will not do anything until I launch the Flic app. Is this expected? I would like the button to do its thing regardless of whether the app is actually running or not.

Also, when I force-close the app, the button stops doing its action.

Expected or not expected?