[Blue Ocean] Sequential stages appear to be completed but are still executing

pipeline {
agent any
     stages {
        stage('Parallel') {
            failFast false
            parallel {
                stage('Nested B') {
                    stages {
                        stage('Nested B-1') {
                            steps {
                                echo 'Nested A-1'
                            }
                        }
                        stage('Nested B-2') {
                            steps {
                                sleep time: 5, unit: 'MINUTES'
                            }
                        }
                    }
                }
                stage('Nested C') {
                    when {
                        expression { false == true }
                    }
                    stages {
                        stage('Nested C-1') {
                            steps {
                                echo 'Nested C-1'                               
                            }
                        }
                        stage('Nested C-2') {
                            steps {
                                echo 'Nested C-2'                               
                            }
                        }
                    }
                }
                stage('Nested A') {
                    steps {
                        sleep time: 5, unit: 'MINUTES'
                    }
                }
            }
        }
    }
}