I have 2018 S550 and a few months ago began having problems accessing my iphone music through the USB interface. Playlists are jumbled, the iphone continuaaly disconnects from the music interface, search will intermittnetly stop working (greyed out and not accessible). Very glitchy. Haven't ever had a problem up intil a few months ago. Asked the dealer about recent updates to the MB system or incompatibilities with recent ios updates but no one at my dealership even understands what I'm talking about (their answer is "use bluetooth"). Wondering if others are having similar issues?