WebViewRenderer.OnElementChanged gets called with null native control on Xamarin Forms 2.5

I am using my own customrenderer for Webviews it has always worked but since I upgraded Xamarin Forms nuget package to version 2.5 it crashes because it seems like the member method OnElementChanged is called with null Native control and null thisActivity. any idea how to fix it?

this is the error I get:

    Unhandled Exception:

    System.ArgumentNullException: Value cannot be null.
    Parameter name: thisActivity