Revit Crash with this error when using event handlers in pyrevit

Revit Crash with this error when using event handlers in pyrevit has anybody seen this? - it only happens on one computer across multiple computers.

1:< API_ERROR { Microsoft.Scripting.ArgumentTypeException exception(expected int, got NoneType) was thrown from a handler of Autodesk.Revit.Proxy.UI.Events.MessageBoxShowingEventArgsProxy event. The API event handler was registered by application PyRevitLoader (b39107c3-a1d7-47f4-a5a1-532ddf6edb5d). Changes made by this handler are going to be discarded. }

@revitislife
Care to share the code and the use case?

Hahaha - sorry I figured it out literally 10 mins after I made the post. I was somehow subscribing twice to the event handler. which would go haywire if the document is work shared