Is it only at roundabouts? Is it from a standing start? What are the revs doing?
my x5 had a weird hesitation at roundabouts and when coming to a stop the revs would drop a bit, therefore when setting off while rolling, the car was jumping and sluggish setting off. … weirdly it turned out to be a dodgy battery. Have you tested the battery yet?
the alternator would power the car while running so no issues, but as the engine slowed down, not enough power down to the battery and the alternator would smuggle with the load.
I replaced both after the alternator failed, no issues since