Unable to default the 'legal employer seniority date'to transactional date in convert pending worker

In the Convert Pending Worker flow (Redwood UI), the Legal Employer Seniority Date under the Work Relationship Info section is not defaulting to the Proposed Start Date of the worker from the When and Why section. Instead, it defaults to the worker's Assignment Start Date.

Tried defaulting the value using VB Studio -

[[ $fields.pendingWorkerAssignment.whenAndWhy.ProposedStartDate.$value() ]]

But it continues to be overridden by the Assignment Start Date after publishing.

How can we default the legal employer seniority date?