The issue is that these are in two different event receivers. EventFiringEnabled is a thread specific property. The reason it's done this way is that this could cause code from 3rd parties or other developers to function unexpectedly. If you put those into a single event receiver, I would expect that it would work the way you want it to.

I'm looking for an MSDN reference for this.

The issue is that these are in two different event receivers. EventFiringEnabled is a thread specific property. The reason it's done this way is that this could cause code from 3rd parties or other developers to function unexpectedly. If you put those into a single event receiver, I would expect that it would work the way you want it to.

I'm looking for an MSDN reference for this.

Edit:
I cannot seem to find anything about this specifically in any MS documentation. But here is the article where I read about this when I was experiencing the same issue. Notice that the article was from the 2007 days.

Disable event firing in SharePoint when updating a list item outside of an event handler

Upon disassembling Microsoft.Sharepoint.dll, I discovered that the above mentioned method actually sets a static, thread-specific, property of SPEventManager class called EventFiringDisabled