I got my Mazda 3 I touring with the tech package which has the Bose sound system. After about a month I noticed some digital distortion coming from the rear deck speakers. I have already taken my car to the dealer and all they did was update the infotainment system to ver. 31.00 and the issue is still there any ideas on how to fix this issue? Also Centerpoint and Audio pilot have no effect on distortion.