Approvals for subset of Accounts only

Trying to create an Approvals unit that applies to only a single member in my 'Measures' dimension.

We have a have a dimension called Measures (in lieu of Accounts). It contains a member called Request_for_Budget. Want an approvals process that does not lock users out of writing to other Measures in the same Scenario/Version/Entity combination.

Have tried using Approvals Groups with a Measures Anchor dimension. Selected the Request_for_Budget member only. When I start Planning cycle, the test user correctly gets denied write access to the Request_for_Budget member. However, they are also getting denied write access to another data entry Measure.