Glass is pretty stable unless it is exposed to temperture variations, and even then it is still pretty stable, windows would be useless otherwise. My guess is that they are a bad lot of bottles. The fact that they are from 2006 supports this as well.
Welcome to the Whisky Magazine forum, a place where enthusiasts, connoisseurs and professionals can come together to indulge in their passion for all things whisky. Discuss your most recent purchases, reflect on distillery visits and share tasting notes on your favourite drams with other like-minded forum users. Stay up-to-date on the latest industry news and events, and get involved in our regular polls. There’s no better place to get your whisky fix!