Cannot save the implementation layer case designs due to not being able to display the User Reference Field
I cannot save the implementation layer case design that I imported from the framework layer. There is a User Reference Field in the data class of a framework layer. The field is displayed in the approval routing to Specific User in the framework layer. However, the user reference field is not displayed in the implementation layer and could not be slelected from the dropdownn for the routing. In one hand routing is affected, and on the other hand, no other changes are saved as it requires to supply the user reference field before proceeding with any chanegs in the case designer of implementation layer.
What is causing this issue and what could resolve this issue of routing to User Reference Field and being able to save the case designer?