Unity error build 19 - null refrence

On Android:
Error only occurs if I am using Strip ByteCode
If Stripping is disabled, then it works fine.

(10387): System.NullReferenceException: Object reference not set to an instance of an object

E/Unity (10387): at UnityEngine.Events.PersistentCall.GetObjectCall (UnityEngine.Object target, System.Reflection.MethodInfo method, UnityEngine.Events.ArgumentCache arguments) [0x00000] in :0

E/Unity (10387): at UnityEngine.Events.PersistentCall.GetRuntimeCall (UnityEngine.Events.UnityEventBase theEvent) [0x00000] in :0

E/Unity (10387): at UnityEngine.Events.PersistentCallGroup.Initialize (UnityEngine.Events.InvokableCallList invokableList, UnityEngine.Events.UnityEventBase unityEventBase) [0x00000] in :0

E/Unity (10387): at UnityEngine.Events.UnityEventBase.RebuildPersistentCallsIfNeeded () [0x00000] in :0

E/Unity (10387): at UnityEngine.Events.UnityEventBase.Invoke (System.Object[ ] parameters) [0x00000] in :0

E/Unity (10387): at UnityEngine.Events.UnityEvent.Invoke () [0x00000] in :0

E/Unity (10387): at UnityEngine.UI.Button.Press () [0x00000] in :0

E/Unity (10387): at UnityEngine.UI.Button.OnPointerClick

Also applicable to BUILD 20

Bug #?

Sorry I keep bug reporter off. I am little skeptical of bug reporter. It is not fully transparent to me which all information it does collect and send.

I can’t fix this unless there is a bug where I can reproduce the issue logged in our bug tracking software.