Ignition Coils Misfiring anyone?

ICENINE

Hey guys, I was just wondering if anybody else has had this problem. My "Service Engine Soon" light came on so I took it to the dealership. Turns out an ignition coil went bad. They replaced all six because the guy said if one fails the others will eventually follow. My car is still under factory warranty until next June. So they replace all six and two month later my light turns on again. I take it back to the dealership and they tell me one of the ignition coils is misfiring again. They're going to run some tests to see what's causing it. I called them today and they said they were going to replace a valve sprocket :/ Hopefully that works...if that fails, the guy at the dealership said they might order me a new engine. Anybody has had this problem or is just my Zoe? :/ Thanks for any input in advance.