https://www.mashed.com/135144/the-real-reason-mcdonalds-ice-cream-machines-always-seem-to-be-broken/#:~:text=The soft serve machines also,head start on closing up.
Turns out, the soft serve machines must go through a laborious cleaning cycle that can last hours. The process isn't simply wiping down the machine, but involves an 11-step process that includes using a sanitizer/warm water mix to clean seven removable parts. There are also two irremovable parts that must be scrubbed for at least 60 seconds, before the entire outside of the machine is wiped down with a sanitized towel.