Hello,

could you explain how to reproduce the issue.

I tested with Vuforia Core Examples with 9.8.11

There we have the scene 3-VuMarks in the folder Assets/SamplesResources/Scenes 

When open the scene we can see the VuMarkHandler object which has component  VuMarkHandler.cs script. The VuMarkHandler uses the VuMarkManager according to  https://library.vuforia.com/sites/default/files/references/unity/classVuforia_1_1VuMarkManager.html

e.g. when we check the code we can see

...

void OnVuforiaStarted()

    {

        // register callbacks to VuMark Manager

        this.vumarkManager = TrackerManager.Instance.GetStateManager().GetVuMarkManager();

        this.vumarkManager.RegisterVuMarkBehaviourDetectedCallback(OnVuMarkBehaviourDetected);

        this.vumarkManager.RegisterVuMarkDetectedCallback(OnVuMarkDetected);

        this.vumarkManager.RegisterVuMarkLostCallback(OnVuMarkLost);

        this.vuforiaCamera = VuforiaBehaviour.Instance.GetComponent<Camera>();

    }

...

Testing the scene was working fine - so means the VuMarkManger was working fine in 9.8.11. How did you detect that it was not working? Could you , please, verify with the Vuforia Core Samples? Thanks!

BR

Vuforia Engine Support