Search Results: flirting while you have a boyfriend

There is this girl I kinda work with. She works in the warehouse I get product from, but we used to work together a year ago. For a while there seemed to be mutual flirting and it was cool until she got a boyfriend, and after a while she became super hot and cold with me.
She'd one day come to me asking me for favors, relationship advice, or ask me something random, then the next day she wouldn't say anything and act like I kicked her dog. Then she'd yell, like actually yell, at me if I didn't say hi to her.
She even went off on me because a customer told me I looked twice my age, and I felt very self conscious and asked her how old I looked and she said age didn't matter, my question didn't matter, and she had a boyfriend anyway... Like ok.
But anyway, I got promoted to my current spot now, and since she goes out of her way to make sure I see her while I'm there. But she is still either rude or super nice. Last week, she was goofing around with someone I was talking to and I tried to take her phone playfully, and she said in a sarcastic (?) Way I was mean. She didn't mean that, but I said that I felt she was usually mean to me if I saw her, and she pouted and walked away.
But a few days ago, she was doing the same thing and I did the same thing, by taking her phone, and this time she went, "are you fucking kidding me" and we all were kind of taken aback. I apologized, gave her phone back and left. I was only being playful and the people around me knew I was kidding.
But what I'm worried about is, we've just been doing our sexual harassment training, and she apparently was in a bad mood from her meeting. Should I be worried about any issues from this? I know I absolutely need to stay away from her. But I just don't want to lose my job for a little horseplay.