When you feed they have different instincts in feeding mode.
You are a moving predator to her, she is not used to you when she's eating. As far as she can tell, you're a threat to her and she will sacrifice her meal to save herself like she would in the wild.
Once you see her kill the rat or mouse, I would leave her alone in the dark with NO traffic by her cage for at least an hour, maybe more.
Also, I recommend feeding one properly sized prey item per meal instead of trying to feed two.
You should be offering her food every week. After a regurgitation though, you should wait two weeks.
The double kill of mice could have been a factor of the regurgitation as well.