I have the same hiccup on mine and I only notice it exactly as you've described. Only under low load and leisurely acceleration. I however suspect its the supercharger clutch engaging because of when it happens. Always at the same RPM. If I move out briskly it doesn't occur even the first time I use the car for the day. However it will do it after driving for a while if I'm stuck behind a Granny leaving a light, or similar situation, just not as noticeable. Soooo, your not alone.

Les