Supervisor is a jerk

So on Friday I received an email from my supervisor asking me to make a correction on a document. I got busy with something emergent and forgot, so she sent another email a while later. This time the email was a forwarded chain of emails apparently discussing the error. Another supervisor had originally emailed my supervisor saying there were some "inconsistencies" with my work in the document. My supervisor responded to her saying "Of course there were." She didn't mean for me to read that part because she edited it out in her first email to me, but forgot in the second. I fixed the error and responded back to her that I don't appreciate my supervisor speaking about me like that to other supervisors who have nothing to do with me.

She's had personal issues with me since becoming supervisor just a couple months ago. She's already been caught once bad mouthing her employees to another supervisor, and here she goes again. She has yet to respond to my email calling her out on her behavior, so I'm expecting her to come into my office tomorrow to "apologize" in person, even though it's fake. I just don't understand how she can say to my face that I do good work, she rarely has to ask me to make corrections, blah blah... and then behind my back, tells another supervisor that I'm basically a screw up always making mistakes. What would you do?