Checking at the moment if it is a local issue with my supervisor setup (corrupted something) or if this is a problem with me using packages:
When I create the script as yaml in packages, it works.
When I create it manually in scripts.yaml or save it via UI(which is written to scripts.yaml) neither show in the UI.
So the scripts.yaml entries are not shown in the UI. So maybe incompatibility with packages? All scripts in packages worj flawlessly (including these datetimes).