I was able to resolve the issue I was facing with the kotlinx.serialization.SerializationException. After some troubleshooting, I discovered the root of the problem was related to two things:

Initialization of the route class: I needed to ensure that the route class is initialized with default or null values.

Setting the correct startDestination in the nested navigation graph: I had to use GroupDetail() as the startDestination when defining the navigation graph.

Solution Step 1: Initialize the Route Class with Default/Null Values

The first issue was with the initialization of my route. I needed to ensure that GroupDetail was initialized with null or default values when declaring the start destination in the navigation graph.

@Serializable
data class GroupDetail(val id: String? = null)

Step 2: Define Nested Graph with Correct startDestination

In my nested graph, I was missing the proper initialization of the startDestination. The solution was to ensure that GroupDetail() (with null/default values) was passed as the startDestination.

Here’s the updated navigation setup:

fun NavGraphBuilder.groupDetailNavGraph(rootNavController: NavHostController) {
    navigation<GroupDetailGraph>(
        startDestination = GroupDetail() // Ensure to use GroupDetail() here
    ) {
        composable<GroupDetail> { backStackEntry ->
            val group: GroupDetail = backStackEntry.toRoute()
            GroupDetailScreen(rootNavController = rootNavController)
        }
    }
}