I have experienced a jerking or pulsating on acceleration in that RPM range on my 2013 28i.
I asked the dealer about it and they said they couldn't reproduce it and it was likely due to the gas I was using. Of course.
I don't think its the transmission though. Because I've gone into manual and experienced it too.
Interestingly, I haven't experienced it since the weather here has cooled off. Seems like I will have the issue occasionally if the temp outside is above 85F or so.