Seems like a serious problem with the Rex if it has occurred repeatedly.
2. The dealership sales guys said that this has happened to 6 REXs in Canada and also in US for which he did not know the numbers.
Sounds like a manufacturing Q/C failure somewhere in the process, likely on a set/small batch of engines. Shavings left in the engine after drilling/tapping for spark-plugs when a clean-out process/step failed or was missed, maybe?
2015 i3 Rex, Capparis White, Tera World, Technology & Driving Assistant, Parking Assistant, Harman Kardon Audio System, 19 inch 427 wheels, EVoInnovate EVSE