Hi,
Could you maybe export the group to CSV and send it to support@inductiveautomation.com, or post it here? I want to be sure that I understand how it is set up. Also, could you go to the Log Viewer and export the errors, so I can see where they’re coming from exactly?
Since the errors seem to be related to asynchronous writing, you could try switching it to use the synchronous write method, just to see if that changes anything. You can do that under Settings>Service Settings>OPC Settings.
Regards,