Never had this flavor, but TFA Ripe Banana had a horrendous chemical flavor attached to it... and it did not go away. Not even with the super duper magic of steeping
Sometimes you just find one that doesn't work, and all flavors are certainly not created equal.
You can try giving it a nice warm bath, leaving the cap off, setting it aside for weeks, months even. But I'd wager that the flavor won't change to your liking, even after all of these practices. Just my experience - were it me, I'd
throw it out.