How to default an extensible flexfield in additional assignment info section during a transfer

Summary:

Hi expert,

I would like to know if it is possible to nullify an extensible flexfield in additional assignment info section each time a transfer is made.

this is the section I would like to edit

this is the rule I configured, an object defaulting rule type

When I perform a transfer I get this error after clicking continue in when and why section.

Is it possible to implement a rule as described?

Thank you,

Alessandro.