Because of some other technical issues we have to work in Unity 2019.2.0a8 and unfortunately on iOS when enabling Vuforia, it gives us a "brown" screen.
We have disabled the "Auto Graphics API" and set it up to use "OpenGLES2" only.
We have tested this same build for android and can confirm that it works there.
I've uploaded the log to pastebin.
We do realize that technically alpha's are not supported however it would be great if someone can help us point out the issue if it lies within our configuration of vuforia/unity.
In advance thanks for your help!