From this question, it seems I can set start destination argument by passing them as default values but the following code is giving me an issue.

val route = "FORM_DECISION_QUESTION/{FORM_DETAIL_ID_KEY}/{FORM_QUESTION_ID_KEY}?FORM_PARTICIPATION_ID_KEY={FORM_PARTICIPATION_ID_KEY}"
 NavHost(
        navController = navController,
        startDestination = route,
        modifier = modifier,
    ) {
composable(
        route = route,
        arguments = listOf(
            navArgument(FORM_DETAIL_ID_KEY) {
                type = NavType.StringType;
                defaultValue = "453"
            },
            navArgument(FORM_QUESTION_ID_KEY) {
                type = NavType.StringType;
                defaultValue = "534"
            },
            navArgument(FORM_PARTICIPATION_ID_KEY) {
                type = NavType.StringType
                nullable = true
                defaultValue = null
            }
        )
    ) {
//logging the argument values here

SingleFormDecisionQuestion()
 }
}

When I log {it.arguments} I get
Bundle[{FORM_PARTICIPATION_ID_KEY={FORM_PARTICIPATION_ID_KEY}, FORM_QUESTION_ID_KEY={FORM_QUESTION_ID_KEY}, FORM_DETAIL_ID_KEY={FORM_DETAIL_ID_KEY}}]
which is not What I expect but when I navigate to that destination from a different destination
I get
Bundle[{android-support-nav:controller:deepLinkIntent=Intent { dat=android-app://androidx.navigation/… }, FORM_PARTICIPATION_ID_KEY=4, FORM_QUESTION_ID_KEY=3, FORM_DETAIL_ID_KEY=14199608}]

Which is what I would expect.