Error: Invalid Value Details: Failed invoking <symbol>

Hi

Any idea why line starting with "var testCalc...." causes the app to crash with Error: Invalid Value Details: Failed invoking <symbol> . I have tried some many things to try resolve it. Any help would be appreciated

import Toybox.Application.Properties;
import Toybox.Activity;
import Toybox.Lang;
import Toybox.Time;
import Toybox.WatchUi;

class ChowTimeView extends WatchUi.SimpleDataField {

    private const FIELD_LABEL = "Eat Time";
    private var eatIntervalSeconds = 0;

    function initialize() {
        SimpleDataField.initialize();
        label = FIELD_LABEL;
        eatIntervalSeconds = Properties.getValue("PROP_EAT_INTERVAL_MINS").toNumber() * 60;
    }

    function compute(info as Activity.Info) as Numeric or Duration or String or Null {
        
        var elapsedTimeInSeconds = info.elapsedTime / 1000;
        System.println("ChowTimeView : compute : elapsedTimeInSeconds : "+elapsedTimeInSeconds);   

        var testCalc = eatIntervalSeconds / elapsedTimeInSeconds;     
        

        return 0.0;
    }
}

Thanks in advance!