X7 stop sale?

Hi everyone posted last asking about owner experience with the x7. Well you convinced me to grab one and had everything setup to go pick it up this Friday. My salesman just called me and told me they just got word about a stop sale on x7’s and many other bmw models. I asked if they had a timeframe or information on what it is and all he knows is it has to do with the braking system. Has anyone heard anything about this issue and what the cause is or if there is a fix in the near future? My salesman has even mentioned possibly unwinding the deal and to have a backup vehicle if need be. Any info would be appreciated.