If you can find it maybe inside the bottom of your bag, it is an easy home fix with a little epoxy glue.

No excuses for this still happening

"Just over a year" is outside the 1 year warranty, but I would contact your club from which you purchased them or call Titleist customer service directly.

I have also experienced the back cover falling off two of my Titleist T350 irons. My 5 iron and my 8 iron. I had my club pro contact Titleist and they gladly provided me new Iron heads and matched my seriel numbers. I live in the mid west and including transit time to Sunny CA the repair time was just over a week. I was very pleased with Titleist customer support and response time. One backplate fell off inside a year of purchase and the other came off about 14 months after my purchase.

I am looking forward to their new iron refresh and hoping they utilize a little more or stronger epoxy.

The good news is that Titleist has been taking care of their customers just like TM has done with their drivers. I know that there is no OEM out there that hasn't had quality issues in the past. I'm a bit surprised that Titleist hasn't address this problem much sooner. Well at least they knocked it out of the park with their drivers in the GT line up

This is where Titleist excels...great customer service that exceeds expectations They'll take care of you, I'm sure.