Crash in OnResume in Android app

E/mono-rt (15718): [ERROR] FATAL UNHANDLED EXCEPTION: System.NullReferenceException: Object reference not set to an instance of an object

E/mono-rt (15718): at Test.Test.TestFragment.OnResume () [0x00000] in :0

E/mono-rt (15718): at Android.App.Fragment.n_OnResume (IntPtr jnienv, IntPtr native__this) [0x00000] in :0

E/mono-rt (15718): at (wrapper dynamic-method) object:989b7125-a6b4-4b87-aef4-b05788e6af73 (intptr,intptr)

I/ActivityManager( 451): Process Test.Test (pid 15718) has died.

I am getting the following error when I bring my app to foreground, In my OnResume function first line is base.OnResume() and then there is crash. Any inputs on this or is this another Xamarin bug. This happens rarely not everytime though.