Symbol Not found error

Hi,

I have several reports from ERA (and one user has emailed me) to say that my app is crashing when trying to run a specific function of the app. This function stores some data in storage.

The code is:

    function saveToStorage(tileData){
        var tileId = tileData["info"]["id"].toString(); 
        //System.println("Saving Tile Id " + tileId + " to storage.");
        
        try{
            Storage.setValue(tileId, tileData);
        }catch (ex instanceof StorageFullException){
            //System.println("Storage Full");
        }
        catch (ex instanceof UnexpectedTypeException){
           //System.println(ex);
        }
            
        
//        if(AppConstants.DEBUG){
//        }
    }

The error is:

Error Name: Symbol Not Found Error
Occurrences: 11
First Occurrence: 2021-09-23
Last Occurrence: 2021-10-06
Devices:
fēnix® 6 / 6 Solar / 6 Dual Power: 19.20
Forerunner® 245: 7.80
vívoactive® 3: 7.80
Venu® Sq: 2.90
App Versions: 0.0.31
Languages: ces, dut, eng
Backtrace:
MapTileLoader.saveToStorage:170
DownloadRouteMap.onReceiveTile:261

The line in question is:

Storage.setValue(tileId, tileData);

The Forerunner 245 that the user has emailed me about should be running 3.2, and I have run exactly the same code in the simulator using the same input data and it works just fine.

Can anyone suggest where I should be looking to understand why this isn't working for a small number of people in some cases? 

The user who reported it reported that it started happening a few days back (no release of the app) and now affects any route he tries to load, even ones which were previously OK.

I will ask him to run some logging, but can the value of tileId cause this error if, for example, it were null? 

Thanks

David