That's a nice way of saying, lately she's been wearing some plunging necklines to work. I call it a "fashion issue" because there have been a lot more tops of that sort out on the racks lately, being presented as "business wear." I rejected a lot of tops on that basis the last time I was shopping.
I suppose when she's standing up looking in a mirror it looks acceptable to her, but if she slouches in her chair in a meeting, you can see... more than the TV network used to allow on original Star Trek.
Her boss is a guy, and so is his boss. So they're probably just averting their eyes and dodging the issue.
Should I mind my own beeswax, or risk ticking her off?
[as an aside... I used to watch "House" a lot and the hospital administrator was always wearing low-cut tops, and I always thought that's so Hollywood, a real hospital administrator would never dress like that. And then one time House made a comment, and she said "How dare you make such a comment," and he said "Well, they're right out there for everyone to see, I figured they were fair game." I said YES!!!]