Aircon - "My Schedule" no longer working

I have four wind free aircon units.
All were successfully linked to smartthings after installation and continue to work fine via manual operation from the app (and from Google home hubs after linking to that account).

Immediately after they were installed, I set up some recurring operation times under the My Schedule option. These worked exactly as expected. However about a week ago they all stopped working and I can’t get them to operate again.

I’ve tried deleting the recurring schedule items and recreating them. I’ve tried deleting smartthings app and reinstalling it. Neither has worked. Any suggestions?

Without being able to setup recurring on/off events, these units become a lot less worthwhile. Idont have any equivalent problems with other smart tech in the home, nor with our original and separate Haier aircon unit in our garden room.