I am also having this issue after upgrading my Unity version and then subsequently getting Vuforia through the package manager, it was previously manually installed into the project.
In the android logcat I am getting:
2019-08-20 11:14:34.846 9366-9408/? E/Unity: UnityAndroidPermissions was not correctly set. Please make sure you have not deleted any files in the Vuforia/Scripts/Internal directory.
Vuforia Engine Version: 8.3.8
Vuforia Engine Unity Extension Version: 8.3.8
Unity Editor Version: 2019.2.0f1
Unity was upgraded from 2018.3.4f1
My app doesn't hang, but it doesn't display a camera view either, the camera would be all black, and even though the app was given camera permissions, I still am getting this issue. I had removed the old Vuforia folder that was manually installed in the project, after having installed Vuforia using the package manager, which then caused some conflict issues to show up in the editor log. After removing the old Vuforia installation I was able to make builds, but then the camera wouldn't load. The error says to not delete any files in Vuforia/Scripts/Internal, but I deleted all of the Vuforia folder that was previously installed, now it is in the packages folder because it was installed through Package Manager. I'm not sure what to do, any help would be greatly appreciated.
I've enabled delayed activation in Vuforia settings, and I am initializing Vuforia in the beginning of my AR scene. I also tried with delayed activation disabled, which gives the same result.
Quick Edit Update:
I've got it to work in one instance, but then it doesn't work if we close the app and open it again. On a fresh install with Delayed Activation disabled, it was able to ask for camera permissions on start up and then the camera worked, but after closing the app and opening it again, it would hang on a black screen with the "UnityAndroidPermissions was not correctly set." issue
I managed to fix it by enabling Delayed Activation again, and adding a bigger delay between the initial app start and the Vuforia initialization.