Realm.Callback() does not call onError(exception: Throwable) when there is some problem while initialising realm sync using flexible sync using java sdk

I have an android app which uses flexible sync configuration for device sync
we first logs into realm then we try to get the realm instance Asynchronously
i create my config as

 val config = SyncConfiguration.Builder(realmApp.currentUser())
        .waitForInitialRemoteData()
        .errorHandler { session, error ->
            // do some error handling
            Log.e("realmInstanceCreation","failedonconfig")
            error.errorMessage?.let { Log.e("realmInstanceCreation", it) }

        }
        .initialSubscriptions { realm, subscriptions ->
            subscriptions.addOrUpdate(
                Subscription.create(
                    "cachereporttypes",
                    realm.where(cachereporttypes::class.java)
                        .equalTo("clientId", obj)
                )
            )
        }
        .allowQueriesOnUiThread(true)
        .allowWritesOnUiThread(true)
        .build()

then i try to get the instance using this configuration as

  Realm.getInstanceAsync(config, object : Realm.Callback() {
                            override fun onSuccess(realm: Realm) {
                                Log.e("realmInstanceCreation","success")
                                realmInstance = realm
                                if (createInstance == 2) {
                                    realmInstance?.close()
                                    realmInstance = null;
                                }
                            }
                            override fun onError(exception: Throwable) {
                                Log.e("realmInstanceCreation","failed")
                                super.onError(exception)
                            }
                        })

when there is proper internet,device sync set up correctly it works properly by calling onSuccess()

I tried failing the getInstanceAsync by turning of internet,then turning off device Sync,doing schema mismatch error in all 3 places it calls getInstance but neither onSuccess nor onError gets Called