Why does an Oracle DRM script fail to update a list property to a blank value using workflows?

When I use the update workflow in Oracle DRM (version 11.2.16) and run a script to update the value of a list property that contains multiple values, including a blank value, I face an issue. When I try to update the property from an existing value to a blank value, the update does not work as expected—the original value remains. I have to manually select the blank value for the update to succeed. This issue only occurs when updating to a blank value, not in other cases.