Found a bug:
See groovy code line 597 'alertSwitchOff ' there is a trailing space inside the string. The actual setting is stored as alertSwitchOff (no space), so bIs(set,'alertSwitchOff ') always returns null/false. The switch-off code on line 604 (dev.off()) is therefore never reachable unless alertSwitchReset is true which only happens when the weather-type-watch feature is active.