Unsure how delete interval works

[Diatosta]

Hi, I've configured my Watchlistarr setup to have a deleteInterval of 16 days, which, according to the comment in the config file, seems to indicate that the content would only be deleted after those 16 days have passed after un watch listing it.

## Number of days to wait before deleting content from the arrs (Deleting must be enabled). DEFAULT: 7
  interval.days: 16

And the logs seem to show that this has been enabled correctly:

Configuration:
  refreshInterval: 10 seconds
...
  DeleteConfiguration:
...
    deleteInterval: 16 days
    deleteFiles: true

However, when I try to unwatchlist some content, it seems that it is done instantly? Or atleast instantly after a reboot of the container?
Because I removed the movie from the watch list, and saw nothing in the logs, even after waiting about 10 minutes.
So I rebooted the container, and then, after showing the config, it logs this line:
14:05:34.582 [io-compute-3] INFO PlexTokenDeleteSync$ - Deleted The Menu from Radarr
And it does indeed remove it from Radarr.

So my question is, is this intended behaviour? As in, I'd have to wait 16 days for it to show on the logs and be removed if the container kept running, but if I restart the container it's instant? Or not?

Thanks in advance :)