Mine did it only on the Autobahn at high speeds, very sporadic, no warnings whatsoever. Only thing the BMW Dealer thought it may be was during a DPF burn but again this only happened about 8 times over a 4 month period then disappeared. 90,000 KM since with no issues like that.
I’d just keep driving, if possible long Autobahn trip in Sport Mode and hope it goes away, other than that to a BMW Dealer who may find nothing - for a steep price.
How many KM’s you have ? If > 150,000 have someone do an Endescope Inspection of the AGR Trakt. Takes 15 mins.