Belt splitting down the middle

Today i started my truck and it was making a weird ticking noise and i noticed the belt that drives the alternator is split down the middle. It's not broken and still turns everything but it's split. Toyota put new belts around 2 years ago for $200 and i haven't messed with them since and now this happens. I'm taking it to them tomorrow to see what they tell me. I expect to get more than 2 years of life for 200 dollar belts. Will this be covered under warranty? How long do belts last for? Talked to them briefly today but they were about to close and they sounded like they were not going to cover it because they were telling me it might be the tensioner. In the end they told me to just bring it tomorrow morning.

 

My belts are 10 years old and are still okay.