This has happened to me. One Sim got a midlife crisis just hours before the game patch on October 22, 2024. She got the usual 7-day timer buff, which decreased as she did tasks on her list, and finally the crisis was resolved (in less than 7 Sim days). Her husband got a midlife crisis just a few (RL) days ago. I've been playing him for a Sim week now; his tasks keep checking off and renewing, but he has no timer buff, and I'm starting to wonder if it will ever resolve. I honestly didn't notice if he had the buff when he first got the crisis or not, and I don't have a save that dates to that point in time.
I do have MCCC, but it's my only script mod, and it was in for both instances. I did update the mod to the most current version after the patch. If the task list never goes away, I guess it's alright. He's carefree and doesn't get tense about it, nor does he get scared that time is passing. He does sometimes contemplate life, but don't we all.