Is the car new to you, or have you had it for a long time and this "slipping" symptom is something new?
Does the symptom appear particularly when you suddenly re-apply throttle after slowing into the turn?
There have been reports of the transmission "hunting" momentarily in some circumstances, such as turning. It seems to happen if, just after releasing the accelerator, it's advanced again. As the car slows, the tranny normally downshifts in stages, both to make use of engine braking and to make sure the transmission is in the most suitable gear for that speed. If it's caught just at a switching point when the accelerator is pressed, it might hesitate as it "decides" which gear to use. There's no unusual revving of the engine; just a sort of pause. (The appearance of "slipping" might be sensed because during shifts, which normally take afraction of a second, the electronic engine control actually cuts the throttle to reduce the potential for shift shock and stress on the drive train. So there's a sense of loss of "power".)
This phenomenon has been reported here before, and I've experienced it on my 07 as well early on.