Ain't no mystery - they do fall out. No doubt the adhesive used has a short life. As Soren and Ray indicated, the lens can be replaced by prying the lens out by placing your finger nail under the chrome ring that houses the lens itself. No need to remove or loosen the consol. The lens replacements are ready available at most dealers.
My suggestion - BEFORE YOU LOSE ANOTHER, as they are expensive for what they are.
Remove ALL lens holders and pop the lens off ( You'll probably find them 'ready' to fall off anyway. Using cleas silicon sealant (Automotive or bathroom), place a very small amount where the lens fits the housing and press the lens back on. Wipe away any excess, and allow the sealant to 'set'. You'll be glad you did.
