Well, hope you learned that people aren't what they seem to be so you can be more cautious in your approach going forward at least.

Either way, it's not really advised behaviour to be that frank about your boss to her boss, it's a bad look in any case. You basically snitched on her, regardless of what your intentions are, and that's just not smart. I'm sure we've all heard of how the saying about snitches go.

Like I said, in the future, if this happens again and you genuinely want to help your boss, don't bring her up in the conversation. Express to him that you're doing your best but the department is lacking resources, and see if there might be alternative solutions involved without bringing others in the conversation. It's corporate 101 really.