I'll be watching it too! Haha!
I read your post. My workaround is simpler, but still not the elegant method I want:
I run a FOR and assign each value to the new ArrayCollection variable.
And that basically stops the binding when editing values in testAC, but again, that is not an elegant way of doing this.
There must be a better one.
But I'm curious if you have bindable objects inside the original AC.