2011 X3 x28i Intermittent power loss

So Under acceleration, specially from a lower speed / high gear (like 65kmh on gear 8), every so often when I accelerate softly from this point, suddenly my X3 jerks anywhere from 1-5 or 6 times, very noticeable, and then changes gear.

Once in a while it jerks so hard that the I suddenly get a drivetrain malfunction warning on the nav screen and in the instrument cluster + heavy shaking/shuddering for a few moments and then it all goes away. This happens about 30% of the time.

Took my X3 in, they replaced the transmission but the problem is still there.

Now BMW does not know what the issue is. There is no fault code and every time I take it in, I go for a drive with the shop manager and the problem doesn't show itself. So they just have no idea what the problem is specially after having replaced the tranny.

My 2011 X3 has 115,000kms and is on extended warranty.

Any comments or suggestions is appreciated.

Thanks

2011 X3 x28i Intermittent power loss