Unable to Disable or Grey Out MPA and Distribution Dates After Invoice Approval

We are facing an issue where the MPA dates at the line level and the distribution dates are still editable even after the invoice is approved.

We attempted to disable (grey out) these fields based on the approval status using the following condition:

#{bindings.ApprovalStatus.inputValue == 'APPROVED' || bindings.ApprovalStatus.inputValue == 'WFAPPROVED'}

However, the condition always evaluates to false, and the fields remain editable after approval.