Lately, when I've been upgraded via status to Comfort+, if I don't want the center seat the system hands me, the website won't allow me to change my seat back to regular Econ. I get the red exclamation point and "We are unable to process your seat request at this time. Please try again later."

Is there a workaround on this? (Other than calling, which I hate to do for seat selection.)

UPDATE: App won't let me move back either. WTH?