System Error on Application.Storage

Over ERA I've got this message:

Error Name: System Error
Occurrences: 2
First Occurrence: 2023-11-02
Last Occurrence: 2023-11-02
Devices:
Edge® 1040 / 1040 Solar: 18.25
Edge® 1040 / 1040 Solar: 18.25
App Versions: 1.0.1
Languages: cht
Backtrace:
EdgeAllinOne1View.initialize:605
EdgeAllinOne1App.getInitialView:43


Line 605 in View.mc is - (and I think it is this line really):

Application.Storage.setValue("prozSOC", 0 );

Here I store (initialize) a value for later refresh and use in following activities.
This error happens apparently only occasionally.
Never happened to my 3 devices Edge 1030, 1030 PLUS, 1040.

What can "System Error" mean here?
Usualy there wil be created a file system in Garmin\Applications\Data.

Maybe a problem with the file system on the device?