I can't do a rule 'must be unique' with a Datetime.
On MSDN web site, it suppose to be working...
The selected attribute must be unique independently or in combination with defined attributes.
This action is valid for numeric, string, and date values.
Best Practice: Combine this action with a mandatory condition to ensure validity of index fields in subscribing systems.
Does the problem happen when you specify "must be unique" rule with one Datetime attribute or does it happen when you combine Datetime attribute and Numeric attribute?
Please let me know the detail condition to reproduce the issue.