Some flavors are just great when you get them fresh. Others will taste 'off', or downright nasty. I had purchased a 'vanilla swirl', and when it first arrived it had a taste that brought to mind 'vanilla paint thinner'. A week later, it tasted more 'vanilla', and less 'paint thinner'. Another week later, it was great! Just like I expected! Other flavors purchased in that sampler were good as soon as I received them, and still tasted the same a month later.
I guess some blends need more time to 'blend' than others.