Attestation properties are not displayed as configured in web portal attestation case details

Hello experts.

I have a question regarding an attestation case. We created a custom attestation procedure where we have to display the values for an attestor to approve or deny a new value of a certain attribute.

However when the attestation case is generated and published in the web portal for an attestor to approve or deny a change, the details do not show the display values from attribute Property 2 and Property 3.
Instead of Mobile phone in both cases, the display value should be "Old mobile phone number" and "New mobile phone number" as written in attributes Property 2 and Property 3.

Version of Identity Manager is: 9.1

Has anyone ever had a similar experience and how did you solve this issue?