Thank you for the screencast. I reproduced the problem, but it is more related to a problem with this specific content and it is also reproducible with a simple editable iframe element. In the attached clip you can see that in the copied content there should be an $nbsp; entity, which is missing after zooming the specific test.
Due to the reason that this is not a problem related to the editor's implementation we are unable to provide a workaround or fix such issue.
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