This irks me. I feel like, you sign up with them during that Open Enrollment window, October to December, that's a commitment on your part. In my eyes, that's like a contract. It IS a contract! They shouldn't be able to change the terms of the contract, willy-nilly, with no notice, arbitrarily like that! In fact that sounds like breach of contract to me! Sue the biscuits! Call the authorities! Shake your fist and go down fighting!
Oh dear. I'm being a rebel-rouser. Gasp, I can't breathe, lol! But it does make me mad.