the only thing I can think of is the gear lever touching the MC piston before it engages, or perhaps too much brake fluid so that the calliper pistons cannot retract after you release the brake lever. I do not believe that anything is wrong with the callipers themselves. bmw dealers are just morons.
speaking of which, someone mentioned that it is not dangerous because of having ABS. it is not true, both the brake pads and the rotor will extremely overheat before the ABS kicks in. i had this situation with Tiger 800 after changing the MC and putting too much brake fluid. My bike stopped, locked the front brakes, in the middle of the road before ABS engaging and the rotor was blue from the heat.
as you love riding, you need to love you bike