I have to admit, I have been this girl.. And let me explain why I myself did it to maybe give you a possible insight:
When my boyfriend and I would fight, I would get so overwhelmed that I would feel sick to my stomach and feel like leaving is my only option. I felt he was difficult to reason with and disregarded my reasons for being upset a lot of the time. I felt like the only time I got the love and attention I wanted was when he was begging me to stay. I would either return or unpack my things based on his grovelling as well as my fear of being alone.
So, with that being said, it could be triggered by your behavior, her insecurities, or both. Or something else completely.. Either way, you can try to sit and talk with her calmly and address the problem and if it continues, I think it's safe to say your relationship is toxic and really should end.
Good luck my friend.