ViewTracker_AttachTracker

Hi, I am using xamarin forms within xamarin android project. Recently after updating my xamarin to current version (Xamarin studio 5.2.1), my previously working project stopped working. The error I am receiving is the error below which is the inner exception in a TypeInitializationException - is this a bug? I am never using in my own code an attach tracker, the error occurs when I initialize a new NavigationPage - any clues on how I may fix it?

Thanks.

Didn't find class "xamarin.forms.platform.android.ViewTracker_AttachTracker" on path: /data/app/DiaForms.Android-2.apk

at Android.Runtime.JNIEnv.CallObjectMethod (IntPtr jobject, IntPtr jmethod, Android.Runtime.JValue[] parms) [0x00064] in /Users/builder/data/lanes/monodroid-mlion-monodroid-4.14-series/8e79d361/source/monodroid/src/Mono.Android/src/Runtime/JNIEnv.g.cs:194
at Android.Runtime.JNIEnv.FindClass (System.String classname) [0x00007] in /Users/builder/data/lanes/monodroid-mlion-monodroid-4.14-series/8e79d361/source/monodroid/src/Mono.Android/src/Runtime/JNIEnv.cs:412
at Android.Runtime.JNIEnv.FindClass (System.Type type) [0x00009] in /Users/builder/data/lanes/monodroid-mlion-monodroid-4.14-series/8e79d361/source/monodroid/src/Mono.Android/src/Runtime/JNIEnv.cs:353
--- End of managed exception stack trace ---
java.lang.ClassNotFoundException: Didn't find class "xamarin.forms.platform.android.ViewTracker_AttachTracker" on path: /data/app/DiaForms.Android-2.apk
at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:65)
at java.lang.ClassLoader.loadClass(ClassLoader.java:501)
at java.lang.ClassLoader.loadClass(ClassLoader.java:461)
at diaandroid.MainActivityForms.n_onCreate(Native Method)
at diaandroid.MainActivityForms.onCreate(MainActivityForms.java:28)
at android.app.Activity.performCreate(Activity.java:5104)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
at android.app.ActivityThread.access$600(ActivityThread.java:141)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5041)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
at dalvik.system.NativeStart.main(Native Method)