Rules not working for Position field set to read only on demotions in Change Assignment page

Summary:

We are finding that a business rule to accomplish the below is NOT working in VBS.

We have attempted to re-apply a customization to the Change Assignment page that configures the Position field as a read only field when processing anything except for a demotion. When processing demotions the Position field should be editable to allow a person to have their position changed for the demotion.

Content (please ensure you mask any confidential information):

To attempt to set the Position field to read only, so that users can see the field and cannot change this field for all assignment changes except for demotions, we created a business rule in VBS Express Mode. This business rule refers to the value in the When and Why section Action field which appears in the Redwood UI with the description of "What's the way to change the assignment?". If this field does not contain the word "Demotion" then the PositionID (Position) field on the page should be set as Read Only. However, we are finding