The best course of action is:
1. Take the bike to the dealer to confirm exactly what the problem is.
2. If it's the same issue as before, call Triumph Customer Support and *POLITELY* explain the situation and that, while you understand the bike is out of warranty and that they're not obligated to do anything, you feel two instances of the same issue on a bike with less than 25K miles is a little suspect.
Whatever you do, don't call them with an attitude. I can tell by reading posts in here that a lot of the folks that complain about Triumph Customer Service probably don't do themselves any favors. Their posts are full of piss and vinegar and that's likely how they talk when they call Triumph. A demanding/argumenative attitude usually doesn't bode well for accomplishing your goal.
Anyway, they may help you out if you're cool, and fair, with them. It would also help if you can show the bike has had all scheduled maintenance performed, and at the prescribed mileage/timeframes.
Good luck!