Hmm, I would think that it all has to do with her getting too much sleep and not enough A time in the daytime. Average A time at 7 months is 2.45-3 hours, there are some sample routines here:
chronological EASY samples, 7-9 months if you want to look and see. When she hits the 2 hour mark, what happens if you try to change the scenery, distract her with an interesting toy or book? With my ds, I used to have to switch rooms every couple of minutes towards the end of A time in order to keep him interested -- walk around, maybe go outside later in your A time if she likes it? Or could you maybe extend the time she's awake after the cat nap so she's getting less nighttime sleep? A lot of LOs have 11 hour nights at this age.
Have you ruled out discomfort as a cause of wakings? Teeth, food issues, etc?