Manager can't edit the Secondary Managed Plan after Submitting the Primary Managed Plan

Summary:

A Manager has the same compensation plan for both Primary Managed and Secondary Managed plan, the Secondary Managed plan's worksheet became read-only when the manager submits the Primary Managed plan for approval.

Content (please ensure you mask any confidential information):

We have a compensation plan that has Primary and Secondary Hierarchy which both have Updates Allowed as the default access level. A Manager has this compensation plan for both Primary Managed and Secondary Managed plan. After the Primary plan was submitted for Approval, the Secondary Managed plan became read-only.

Is this a standard functionality? Is there a way to make the Secondary Managed Plan editable even the Primary Managed Plan is submitted for approval?