My 2nd place bao zhong is over a year old (hasn't been open that long). I just decanted some of my bao zhong from a large mylar ziplock that I keep the bulk of in into my secondary container where I keep only about 40 grams at a time. It tasted unusually good. That's because it was fresh.
I discovered that the Maiko mylar ziplock I was using to hold small portions of my baozhong must be worn out. That's the only conclusion I can make as to why this session is significantly better.
Make sure that whatever's holding your tea, such as an old mylar bag, is still keeping your tea fresh, because apparently these bags break down and wear out.