I too have this problem and as I remember so some others.
The common theory is that this is where the variable valve timing kicks in. The symptoms seem to range from a flat spot with not much variation in revs to a case like yours which includes a misfire- BTW does yours also miss at around 2K and 3K?
Having had a poke around, the misfire ceases if I disconnect the throttle bypass valve- therefore I am leaning towards the idea that the mixture is over-lean- possibly due to an air leak or maybe dirty injectors. It certainly doesn't look as though it's ignition based. I need to try disconnecting the lambda probe next to force the injection into open loop mode- this would richen the mixture slightly as the ECU substitutes a "get home value" for the lambda reading.
The oscillation may or may not be significant, I personally am more worried about the misfire.
The car is booked into Mangoletsi soon, I'll post the results.