I have that problem with my M3W - so spoke to the factory about it - I think its a fault!If u play with your indicator whilst stationary it will not cancel - mine cancels after 10 secs over 10mph which is way too soon - and IMHO dangerous if turning right (or left come to that!)
Sooo going to get this looked at in a few weeks time when in for service at the factory -will post update!