Unable to remove port forward - Appium 1.10.0

.travis.yml

language: android
sudo: false

jdk:
  - oraclejdk8

env:
    global:
        # include $HOME/.local/bin for `aws`
        - PATH=$HOME/.local/bin:$PATH
        # Add $JAVA_HOME/bin to PATH (for Appium executing)
        - PATH=$PATH:$JAVA_HOME/bin

android:
    components:
        - tools
        - extra-google-m2repository
        - extra-android-m2repository
        - android-27
        - add-on
        - extra
        - sys-img-x86-android-27
        - extra-google-google_play_services
    licenses:
        - 'android-sdk-license-.+'
        - 'google-gdk-license-.+'

before_install:
    - touch ~/.android/repositories.cfg
    - node -v

    # set up awscli packages
    - pip install --user awscli

    # Install the rest of tools (e.g. avdmanager)
    - echo y | sdkmanager tools

    # Install the system image.
    - yes | sdkmanager "platforms;android-27"
    - sdkmanager --install "system-images;android-27;google_apis;x86"

    # Install appium and appium-doctor
    - nvm install 9
    - npm install appium@1.10.0 appium-doctor

    # Run appium-doctor
    - "./node_modules/.bin/appium-doctor"

    # Run appium in background and logging to appium_log.txt file
    - "./node_modules/.bin/appium --session-override --log-level info > ~/appium_log.txt &"
    
before_script:
    - aws s3 cp s3://<HIDDEN>.apk src/latest-android.apk
    - echo no | avdmanager create avd --force -n testEmulator -k "system-images;android-27;google_apis;x86"
    - $ANDROID_HOME/emulator/emulator -avd testEmulator -no-accel -no-audio -no-window &
    - android-wait-for-emulator
    - adb shell input keyevent 82 &

script: mvn install

after_failure:
    - cat ~/appium_log.txt

cache:
    directories:
        - $HOME/.m2

appium-logs

[Appium] Welcome to Appium v1.10.0
[Appium] Non-default server args:
[Appium]   sessionOverride: true
[Appium]   loglevel: info
[Appium] Appium REST http interface listener started on 0.0.0.0:4723
[HTTP] --> POST /wd/hub/session
[HTTP] {"desiredCapabilities":{"app":"/home/travis/build/<HIDDEN>.apk","appActivity":"com.<HIDDEN>.app.MainActivity","appPackage":"com.<HIDDEN>.app","appiumVersion":"1.10.0","platformVersion":"8.1","automationName":"uiautomator2","deviceOrientation":"portrait","unicodeKeyboard":"true","platformName":"Android","deviceName":"testEmulator","resetKeyboard":"true"},"capabilities":{"alwaysMatch":{"appium:app":"/home/travis/build/<HIDDEN>.apk","appium:appActivity":"com.<HIDDEN>.app.MainActivity","appium:appPackage":"com.<HIDDEN>.app","appium:appiumVersion":"1.10.0","appium:automationName":"uiautomator2","appium:deviceName":"testEmulator","deviceOrientation":"portrait","platformName":"android","appium:platformVersion":"8.1","appium:resetKeyboard":"true","appium:unicodeKeyboard":"true"},"firstMatch":[{}]}}
[BaseDriver] The capabilities ["deviceOrientation"] are not standard capabilities and should have an extension prefix
[Appium] Creating new AndroidUiautomator2Driver (v1.26.0) session
[Appium] Capabilities:
[Appium]   deviceOrientation: portrait
[Appium]   platformName: android
[Appium]   app: /home/travis/build/<HIDDEN>.apk
[Appium]   appActivity: com.<HIDDEN>.app.MainActivity
[Appium]   appPackage: com.<HIDDEN>.app
[Appium]   appiumVersion: 1.10.0
[Appium]   automationName: uiautomator2
[Appium]   deviceName: testEmulator
[Appium]   platformVersion: 8.1
[Appium]   resetKeyboard: true
[Appium]   unicodeKeyboard: true
[BaseDriver] Boolean capability passed in as string. Functionality may be compromised.
[BaseDriver] Boolean capability passed in as string. Functionality may be compromised.
[BaseDriver] Capability 'unicodeKeyboard' changed from string to boolean. This may cause unexpected behavior
[BaseDriver] Capability 'resetKeyboard' changed from string to boolean. This may cause unexpected behavior
[BaseDriver] The following capabilities were provided, but are not recognized by appium: deviceOrientation, appiumVersion.
[BaseDriver] Session created with session id: e92f9895-7684-413e-9d7f-5a5bec9dff29
[BaseDriver] Using local app '/home/travis/build/<HIDDEN>.apk'
[AndroidDriver] Java version is: 1.8.0_144
[ADB] Checking whether adb is present
[ADB] Found 1 'build-tools' folders under '/usr/local/android-sdk/' (newest first):
[ADB]     /usr/local/android-sdk/build-tools/25.0.2
[ADB] Using adb from /usr/local/android-sdk/platform-tools/adb
[AndroidDriver] Retrieving device list
[AndroidDriver] Looking for a device with Android '8.1'
[ADB] Getting device platform version
[AndroidDriver] Using device: emulator-5554
[ADB] Using apksigner from /usr/local/android-sdk/build-tools/25.0.2/apksigner
[ADB] Checking whether zipalign is present
[ADB] Using zipalign from /usr/local/android-sdk/build-tools/25.0.2/zipalign
[UiAutomator2] Server packages are going to be (re)installed
[UiAutomator2] Did not get confirmation UiAutomator2 deleteSession worked; Error was: UnknownError: An unknown server-side error occurred while processing the command. Original error: Trying to proxy a session command without session id
[UiAutomator2] Unable to remove port forward 'Error executing adbExec. Original error: 'Command '/usr/local/android-sdk/platform-tools/adb -P 5037 -s emulator-5554 forward --remove tcp\:8200' exited with code 1'; Stderr: 'error: listener 'tcp:8200' not found'; Code: '1''
[HTTP] <-- POST /wd/hub/session 500 78376 ms - 1119
[HTTP] 
[HTTP] --> POST /wd/hub/session
[HTTP] {"desiredCapabilities":{"app":"/home/travis/build/<HIDDEN>.apk","appActivity":"com.<HIDDEN>.app.MainActivity","appPackage":"com.<HIDDEN>.app","appiumVersion":"1.10.0","platformVersion":"8.1","automationName":"uiautomator2","deviceOrientation":"portrait","unicodeKeyboard":"true","platformName":"Android","deviceName":"testEmulator","resetKeyboard":"true"},"capabilities":{"alwaysMatch":{"appium:app":"/home/travis/build/<HIDDEN>.apk","appium:appActivity":"com.<HIDDEN>.app.MainActivity","appium:appPackage":"com.<HIDDEN>.app","appium:appiumVersion":"1.10.0","appium:automationName":"uiautomator2","appium:deviceName":"testEmulator","deviceOrientation":"portrait","platformName":"android","appium:platformVersion":"8.1","appium:resetKeyboard":"true","appium:unicodeKeyboard":"true"},"firstMatch":[{}]}}
[BaseDriver] The capabilities ["deviceOrientation"] are not standard capabilities and should have an extension prefix
[Appium] Creating new AndroidUiautomator2Driver (v1.26.0) session
[Appium] Capabilities:
[Appium]   deviceOrientation: portrait
[Appium]   platformName: android
[Appium]   app: /home/travis/build/<HIDDEN>.apk
[Appium]   appActivity: com.<HIDDEN>.app.MainActivity
[Appium]   appPackage: com.<HIDDEN>.app
[Appium]   appiumVersion: 1.10.0
[Appium]   automationName: uiautomator2
[Appium]   deviceName: testEmulator
[Appium]   platformVersion: 8.1
[Appium]   resetKeyboard: true
[Appium]   unicodeKeyboard: true
[BaseDriver] Boolean capability passed in as string. Functionality may be compromised.
[BaseDriver] Boolean capability passed in as string. Functionality may be compromised.
[BaseDriver] Capability 'unicodeKeyboard' changed from string to boolean. This may cause unexpected behavior
[BaseDriver] Capability 'resetKeyboard' changed from string to boolean. This may cause unexpected behavior
[BaseDriver] The following capabilities were provided, but are not recognized by appium: deviceOrientation, appiumVersion.
[BaseDriver] Session created with session id: c6d41d55-3213-4d88-b56c-2a68bb6dbb54
[BaseDriver] Using local app '/home/travis/build/<HIDDEN>.apk'
[AndroidDriver] Java version is: 1.8.0_144
[AndroidDriver] Retrieving device list
[AndroidDriver] Looking for a device with Android '8.1'
[ADB] Getting device platform version
[AndroidDriver] Using device: emulator-5554
[UiAutomator2] Server packages are going to be (re)installed
[UiAutomator2] Did not get confirmation UiAutomator2 deleteSession worked; Error was: UnknownError: An unknown server-side error occurred while processing the command. Original error: Trying to proxy a session command without session id
[UiAutomator2] Unable to remove port forward 'Error executing adbExec. Original error: 'Command '/usr/local/android-sdk/platform-tools/adb -P 5037 -s emulator-5554 forward --remove tcp\:8200' exited with code 1'; Stderr: 'error: listener 'tcp:8200' not found'; Code: '1''
[HTTP] <-- POST /wd/hub/session 500 73322 ms - 1119
[HTTP]