OP has your issue been resolved? I started noticing it in my car yesterday while driving and Im around the same milage as you were when you first noticed it.
2015 F32 435i | Estoril Blue |M Sport
2012 F10 535i | Alpine White | ZPP | ZSP | Tech | Lip Spoiler - retired
2007 E92 335i | Spark. Graph. | ZSP | 6 speed MT | Lip Spoiler - retired