Untradable Evo Ring II and Tradable Evo Ring II stack.

Nexon fixing glitches the day they're discovered? Wat

Not to mention that if they take the game down before midnight, the RAAAAGE from people who didn't have time to make their ring(s) tradable would be intolerable.
This is the one single-point-of-failure of this event, after all. You could miss any other day, or any other seven days for that matter, with no penalty. But if you miss today, you're stuck with an untradeable ring. If you didn't make enough for all your chars, you have a problem.

Fixing it later, maybe even on Tuesday night's server maintenance, sounds more reasonable.