An automation includes a synchronization for a read-only field like Rally Formatted ID to a custom field in a destination system. For example:
Rally Jira
Formatted ID --> custom_text
If the custom text field is updated in the destination system, the value is not written back to the field in a subsequent synch.
This is expected behavior since the cache would indicate that the destination system had been updated most recently and since the field is read-only on the source side, there would never be an update to that field to encourage ConnectALL to rewrite the value to the destination system.
As this is expected behavior there isn't a resolution to apply however a full synch of the item should restore the values.