I fixed it on my project by deleting out the Deploy Stage Once Script from the project. If it is in the project is will throw up an error.  So  you were probably using the Deploy Stage Once Script in the Content Positioning Behavior, put the Ground Plane Stage back in there and turn off Duplicate Stage.

Was this issue fixed? Same problem here

I have the same problem. Config, and version file all says 7.1.34

Hi, I updated to 7.1.34, and this version is what appears in Vuforia Config. I still have the three "Cannot implicitly convert type `Vuforia.Anchor' to `UnityEngine.GameObject'" errors from PlaneManager.cs. Any thoughts?

Hello Numena,

Unity 2018.1 comes with Vuforia 7.1.31 and needs to be updated (within the Vuforia Config) to 7.1.34. What version of Vuforia does you Vuforia Config say it is?

Thanks,

Vuforia Support