The first time the Item Updating and Item Updated events fire it is in response to the document properties changing.
The second time they fire it is in response to the document being checked in.
We may never know about all of the dangers lurking out there, but today we’re going to cover at least one danger you may encounter while writing event receivers – an annoying issue with the Item Updating and Item Updated events firing twice.
Note: when the property editor dialog displays, the user has the option to cancel out of the dialog.
If the user opts to cancel, then only the Item Adding and Item Added events will have fired and the document will be left in a checked out state.
But that option exists to be used, and some people really do need it.
If you find yourself in this situation, then you’ll have to solve the problem in code.
Also note: the Item Updating and Item Updated events that fire in response to the properties being edited from the dialog will always occur, even if the user is not entering or changing any of the values.