Currency Field not editable in test environment

Summary:

We created a Currency field in a Sandbox in our Test environment, and the intention is to make it conditionally editable and conditionally hide it on the page layout based on some other field value. THis is the field level setup in App Composer, and it is updatable.

However, when we put the field on the layout (Deduction Amount 3 in the screenshot), we noticed that it is not editable for us to specify configuration detail. When we try to edit it on the Edit screen, it is a not-editable field.

See below, Deduction Amount 3 is black, and Deduction AMount 2 (text field) is blue and can be edited.