it's bound to happen over time! there is always the wickest link in the chain. I noticed a bigger gap in mine so I sent it back to Oakley for tune-up immediatly.
warranty should be no charge if there is a problem, no warranty is probably $50 - $100, but don't quote me there...Some battery changes are like $30 on watches that require them, so hard to say. Call in and see what they say and let us know