NZBs not deleted from Watch folder after upload. The NZB is imported again and again

Aas per title.

In the past the NZBs were deleted from Watch folder after importing the NZBs in the SABNZBD queue. For quite some time (I don't remember since which SABNZBD version), the NZBs in the Watch folder are not deleted but imported again and again until I delete the NZB file manually from the Watch folder.

Any idea what is going on? I don't think I changed any settings related to authorizations.
Thx