Makes sense I recently helped my grandmother clean out her kitchen cabinet of all the old tea that she didn't want anymore and in the end I ended up throwing out virtually all of it. There was a ROT tin of Blackberry Sage which was at least 3 years old that was so bad when I made it I dumped it out and threw out the rest of the leaves. A 5 year old tin of Twinings Gunpowder green tea (we both got a tin of it my sophomore year of college and I'm in my 3rd year of grad school now), which I didn't even bother to try before throwing it out. There was also a box of chamomile teabags which at first didn't even smell like chamomile and when I tried brewing it 6 teabags stuffed into a single mug only gave me pale yellow water which also did not smell like chamomile either. In the end the only tea that I ended up keeping was an almost empty tin of lemon flavored black tea brought back as a gift from Italy around a year ago which was fairly good.
Seriously before I was a bit skeptical about tea going bad thinking it was mainly a ploy of the tea companies to get one to throw out their tea after a year or so and then buy more but after this experience I KNOW for a fact that tea can and does go bad with age.