The most generous but still realistic interpretation I can come up with is that the girl is attractive, nice, and a little flirty with people. (I don’t see anything wrong with platonic flirting.) Because of these three things, she has a known history of guys, perhaps in particular more desperate guys, thinking she is interested. Her and her boyfriend talk and the boyfriend points out that this may have happened again. So she tells anon about her boyfriend. Anon gets angry. She gets upset because she feels like she is incapable of making friendships with guys without them falling for her and because it’s a pattern she leaves the job out of embarrassment.

That’s being very generous and not believing anon is stretching the truth at all.