Custom Date Attribute Keeps Getting Replaced by "Date Added"

Hi,
I've created the following simple rule:

In the second condition I've created a custom date attribute.
All conditions match as expected.
Upon selecting OK to the rule, I run it, and nothing happens.
When I open the rule again I find that the reference to "short date" in the 3rd condition has changed to "Date Added".
I've repeated several times, each time "Short Date" gets changes to "Date Added"
Help!?
I've created the following simple rule:
In the second condition I've created a custom date attribute.
All conditions match as expected.
Upon selecting OK to the rule, I run it, and nothing happens.
When I open the rule again I find that the reference to "short date" in the 3rd condition has changed to "Date Added".
I've repeated several times, each time "Short Date" gets changes to "Date Added"
Help!?