It could be a couple things.... It almost looks like the some of the leaf tips were burned and then the burned areas rotted from the high moisture. Bromeliads like Neoregelias need to have their foliage dry out from standing water within a few hours save for the cups. The cups can stay full.
I would say it could be getting old as old ones do that but it doesn't seem like you've gotten any pups yet so it can't be that old....