java.lang.IllegalStateException: Multiple representations of the same entity with @ManyToMany 3 entities

I have 3 entities with ManyToMany relationships:

Role Entity:

@Entity
public class Role {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Integer roleID;
    private String roleName;
    private String description;

    @ManyToMany(cascade = {CascadeType.MERGE, CascadeType.PERSIST, CascadeType.REFRESH}, fetch = FetchType.EAGER)
    @JoinTable(name = "role_permission", joinColumns = {@JoinColumn(name = "role_id")}, inverseJoinColumns = {@JoinColumn(name = "permission_id")})
    private Set<Permission> permissions = new LinkedHashSet<Permission>();
}

Permission Entity:

@Entity
public class Permission {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private int permissionID;
    private String permissionName;
    private String description;

    @ManyToMany(cascade = {CascadeType.MERGE, CascadeType.PERSIST, CascadeType.REFRESH}, fetch = FetchType.EAGER)
    @JoinTable(name = "permission_functionality", joinColumns = {@JoinColumn(name = "permission_id")}, inverseJoinColumns = {@JoinColumn(name = "functionality_id")})
    private Set<Functionality> functionalities = new LinkedHashSet<>();
}

Functionality Entity:

@Entity
public class Functionality {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Integer id;
    private String name;
}

I did the following:

1. I have created 3 functionalities:

   Functionality1, Functionality2, Functionality3
   

2. Then created 2 permissions:

   Permission1 with Functionality1, Functionality2
   
   Permission2 with Functionality2, Functionality3
   

3. Then created a role:

   Role1 with Permission1 and Permission2 
   

I am getting the following exception:

java.lang.IllegalStateException: Multiple representations of the same entity [com.persistence.entity.admin.Functionality#1] are being merged. Detached: [com.persistence.entity.admin.Functionality@4729256a]; Detached: [com.persistence.entity.admin.Functionality@56ed25db]

Fixed it by removing CascadeType.MERGE on Permission entity