This from OASIS recently:
May 29 2014 4984 -2013-2014 C-MAX - Frozen Or Delayed Update Of Radio Station DisplaySome 2013-2014 C-MAX vehicles may exhibit an intermittent concern while changing radio stations. The station changes but the screen display does not reflect the station change. The screen may eventually display the correct frequency or channel after a few minute delay. This may occur on FM, AM bands and/or Sirius channels. To correct the condition reprogram the Audio Control Module (ACM) to the latest calibration using IDS release 90.04 and higher. Calibration files may also be obtained at www.motorcraft.com. For warranty claiming use causal part 19C107, and use the applicable 12651D labor operations in Section 10 of the SLTS Manual for the vehicle.