I have the exact same car CX5 GT 2016. It had happened to me once last year. I took out the SD card and cleaned it using a lying around MAF cleaner. It did not help. What helped was blowing some air into the SD card hole using a can of compressed air. I cleaned both the jacks and the USB ports. Only when I cleaned the USB ports did the reboots stop occurring. I have a feeling the USB ports with the SD cart ports are all connected to a single I/O adapter which feeds into the main unit. Try cleaning inside and ANY connected devices 1st.