Property Default Value: activity.date not populating

Summary:

We have a requirement to auto-populate the 'Date' an activity is planned to in an OFS Form. The Users want to be able to see the Date on the form while they are filling in other pieces of information.

However, 'activity.date' does not seem to work when used as a Default Value. The property remains empty.

We can acquire the date by using a message scenario to populate it, but all documentation seems to suggest that this simple default value should work.

Does anyone know why it might not be working and/or how to correct it?

Content (please ensure you mask any confidential information):