The cleaning fee is an additional fee, which is static data that is not automatically synced with booking channels. Whenever the cleaning fee is updated in Rentals United, a manual sync needs to be triggered with PUSH channels, such as Marriott Homes & Villas.
Therefore, once a cleaning fee is set in Guesty, you will have to manually sync them to booking channels connected via Rentals United.
Reach more about syncing static data in Rentals United.