Siri enters loop of requesting parameter when running AppIntent

I want to add shortcut and Siri support using the new AppIntents framework. Running my intent using shortcuts or from spotlight works fine, as the touch based UI for the disambiguation is shown. However, when I ask Siri to perform this action, she gets into a loop of asking me the question to set the parameter.

My AppIntent is implemented as following:

struct StartSessionIntent: AppIntent {
    static var title: LocalizedStringResource = "start_recording"

    @Parameter(title: "activity", requestValueDialog: IntentDialog("which_activity"))
    var activity: ActivityEntity

    @MainActor
    func perform() async throws -> some IntentResult & ProvidesDialog {
        let activityToSelect: ActivityEntity = self.activity
        guard let selectedActivity = Activity[activityToSelect.name] else {
            return .result(dialog: "activity_not_found")
        }
        ...
        return .result(dialog: "recording_started \(selectedActivity.name.localized())")
    }
}

The ActivityEntity is implemented like this:

struct ActivityEntity: AppEntity {
    static var typeDisplayRepresentation = TypeDisplayRepresentation(name: "activity")
    typealias DefaultQuery = MobilityActivityQuery
    static var defaultQuery: MobilityActivityQuery = MobilityActivityQuery()

    var id: String
    var name: String
    var icon: String

    var displayRepresentation: DisplayRepresentation {
        DisplayRepresentation(title: "\(self.name.localized())", image: .init(systemName: self.icon))
    }
}

struct MobilityActivityQuery: EntityQuery {
    func entities(for identifiers: [String]) async throws -> [ActivityEntity] {
        Activity.all()?.compactMap({ activity in
            identifiers.contains(where: { $0 == activity.name }) ? ActivityEntity(id: activity.name, name: activity.name, icon: activity.icon) : nil
        }) ?? []
    }

    func suggestedEntities() async throws -> [ActivityEntity] {
        Activity.all()?.compactMap({ activity in
            ActivityEntity(id: activity.name, name: activity.name, icon: activity.icon)
        }) ?? []
    }
}

Has anyone an idea what might be causing this and how I can fix this behavior? Thanks in advance