You have noticed that after performing a transport request the page layout assignment got reverted to master layout for specific business roles.
SAP Cloud for Customer
This can happen if there are some mismatch in busines roles ID's.
- In TEST Tenant the Business Role ID is maintained as XYZ.
- In PRODUCTION Tenant the Business Role ID is maintained as XYZZ.
When transporting adaptation changes related to page layouts you need to ensure the business roles with same ID. If there is a mismatch the layout assignment is reverted back to master layout.
Temporarily you can just perofrm the assignment of the page layout again. However, after another transport request this issue will happen again.
To permanent correct the issue you need to turn the business role XYZZ obsolete and create it again with the correct ID XYZ.
page layout assignment, business role id, transport request , KBA , AP-RC-UIF-FLX , Page Layout & Key User Configuration , How To