Had a failure of Idler Pulley on 2017 F-Type S at 3800 mi. After hard acceleration merging onto highway/negotiating morning rush hour, I heard metallic/screeching noise coming from engine bay. Alternating messages of: "Electrical System Failure"/"Engine Overheating" displayed. Got off highway, and called for tow. Tech description on repair order said "idler pulley shattered". There is a TSB for idler pulley (SSM73028).
All fixed under warranty so no harm, no foul. Still pretty unusual.

 

did you have any unusual noises under the hood prior to the incident?

 

Not that I noticed.