POR356C

Had a "check left front turn signal" alert recently. While I had the car at the dealer to replace two cam solenoids, they checked out that alert and said that the entire headlight assembly needs to be replaced. Luckily it is still under warranty. So has anyone else had this issue? I searched and found someone with the same alert but no mention of replacing the whole unit. Seems to be a very expensive part. Just to be clear, this is Bi-xenon with active headlights. Don't know if there are other versions out there.
This is a 2012 C300 Sport with P1,P2 and most everything that one gets with those packages. I ordered it about this time in 2012 and it was delivered near the end of July. To date I have had a thermostat replaced, the solenoids, and will soon have the headlight done. At a little under 48K miles on the clock. This has me considering an extended warranty for the first time ever.
Generally happy with the car except for excessive road noise (even after dumping the Conti's it came with it for Michelin's) and a speedometer that is way harder to read at a glance the any car I've driven it the last 50 years.