Could be this!
I have done anatomy research, reading up and all, and find no two folks have the same ability to hear the same sounds all the time? You may hear it, another may not. That said, its likely there, because you hear it! The question is is it doing damage anywhere down there in the inner workings of your bike? Following all the above previous posts suggestions may well be the best here. Document it with your BMW Dealer and IF the warranty goes past, the complaint was filled before so. Something fails, they eat it, imo. Oil usage in engine comments; I used syns years ago, until they got $cost$ prohibitive, still do in tranny and FD, but engine gets regular oil for probably the last 250000miles. Thats a few bikes, with no issues at all. Syns are a great product, but until they get reasonably priced again, I'm out, don't shop for it. Randy