Why does my shared flow subscription not complete after the scope it's shared in is canceled?

ScopeCancel.kt

import kotlinx.coroutines.CoroutineScope
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.Job
import kotlinx.coroutines.cancel
import kotlinx.coroutines.delay
import kotlinx.coroutines.flow.Flow
import kotlinx.coroutines.flow.SharingStarted
import kotlinx.coroutines.flow.flow
import kotlinx.coroutines.flow.onCompletion
import kotlinx.coroutines.flow.shareIn
import kotlinx.coroutines.launch
import kotlinx.coroutines.runBlocking

val scope = CoroutineScope(Job() + Dispatchers.Default)
val flow: Flow<Int> = flow {
    var count = 0
    while (true) {
        emit(count++)
        delay(1000)
    }
}
val shared = flow.shareIn(scope, SharingStarted.WhileSubscribed())

fun main() {
    runBlocking {
        val job = launch {
            shared.onCompletion { println("complete") }.collect { println(it) }
        }
        delay(5000)
        scope.cancel()
        println("isActive: " + job.isActive)
        println("isCancelled: " + job.isCancelled)
        job.join()
    }
}