activitySystemActionForegroundColor(_:) modifier has no effect on action button

When setting a systemActounForegroundColor, no effect is seen on the lock screen when swiping away a Live Activity. Attempted with custom color assets and system colors, but maybe I am using it incorrectly?

@available(iOS 16.2, *)
struct DevicePollingLiveActivityWidget: Widget {
    typealias constants = DevicePollingLiveActivityConstants
    var body: some WidgetConfiguration {
        ActivityConfiguration(for: AlarmPollingActivityAttributes.self) { context in
            DevicePollingLockScreenView(deviceEvent: context.state.device)
                .activityBackgroundTint(.clear)
                .activitySystemActionForegroundColor(.white)
        } dynamicIsland: { context in

            DynamicIsland {
                // Expanded UI goes here.  Compose the expanded UI through
                // various regions, like leading/trailing/center/bottom
                DynamicIslandExpandedRegion(.leading) {```