Can't even describe how many times the latter has occurred to me. It's fucking exhausting.
You CAN get exceptions sometimes but the insurance company can just...decide to change their mind, or not honor it, randomly. Or force you to renew it.
My BF gets monthly harassing letters from United pressuring him to go on a medication that doesn't fucking exist. "Friendly" of course, very "Oh heyyy bestie, we're your cute little gatekeepers, tee hee, and we noticed you were on this dumb little druuuug, so icky and expensive. But how about this other one, the generic? Yeah. It hasn't actually been made available yet or anything, this has been an issue for moooonths but it'd be great if you could swiiiitch. We just enjoy making sure you make the best decisions and would love it if you just, like, became unable to hold the job that gets you insured with uuuuuus." *Intense vocal fry*