Spring data rest ManyToMany mapping PUT/update operation is not replacing the nested object - spring-boot

Question

I started to learn spring data rest. I'm doing PUT operation and it's not working for the nested objects for ManyToMany relationship, whereas it works fine for OneToMany relation.
Entities structures:
#Table(name="CONFIG_DTLS",schema = "app_txn")
#Entity
public class Config {
#Id
#GenericGenerator(name = "UUIDGenerator", strategy = "uuid2")
#GeneratedValue(generator = "UUIDGenerator")
#Column(name = "ID", updatable = false, nullable = false)
private UUID id;
#Column(name = "NAME", nullable = false, length = 75)
private String name;
/*Unable to replace the data in the MBR_CONFIG_MAPPING table in the put operation.
When the control comes to #HandleBeforeSave annotated method in PUT operation,
the request data contains the existing Member info instead of the one which i'm passing in the PUT request body */
#ManyToMany(cascade = {CascadeType.PERSIST, CascadeType.MERGE},fetch = FetchType.EAGER)
#JoinTable(schema = "app_txn", name = "MBR_CONFIG_MAPPING",
joinColumns ={#JoinColumn(name="CONFIG_ID",referencedColumnName = "ID")},
inverseJoinColumns = {#JoinColumn(name="MBR_ID",referencedColumnName = "ID")}
)
private Set<Member> members;
//able to replace the notifications completely in PUT operation
#OneToMany(cascade = CascadeType.ALL,fetch = FetchType.EAGER)
#JoinColumn(name = "CONFIG_ID",referencedColumnName = "ID")
private Set<Notification> notifications;
}
Member.java
#Table(name="MBR_DTLS",schema = "app_txn")
#Entity
public class Member {
#Id
#GenericGenerator(name = "UUIDGenerator", strategy = "uuid2")
#GeneratedValue(generator = "UUIDGenerator")
#Column(name = "ID", updatable = false, nullable = false)
private UUID id;
#Column(name = "OTHER_MBR_DATA", updatable = false)
private String otherMbrData;
}
Notification.java
#Table(name="NOTIFICATIONS",schema = "app_txn")
#Entity
public class Notification {
#Id
#GenericGenerator(name = "UUIDGenerator", strategy = "uuid2")
#GeneratedValue(generator = "UUIDGenerator")
#Column(name = "ID", updatable = false, nullable = false)
private UUID id;
#Column(name="LEVEL")
private String level;
#Column(name="EMAIL")
private String email;
}
Interfaces:
#RepositoryRestResource(collectionResourceRel = "configs", path="configs")
public interface ConfigRepo extends PagingAndSortingRepository<Config,UUID> {
}
#RepositoryRestResource(exported=false) // don't want to users to manipulate it directly.
public interface MemberRepo extends PagingAndSortingRepository<Member,Object> {
}
Here I don't want to add or modify anything in the MBR_DTLS table as it is loaded by another backend process. I want to update only the mapping details MBR_CONFIG_MAPPING table whenever user does the PUT/update operation. POST/create operation is working fine. Please share your thoughts on how to fix this and if you have any questions add it in the comment section.
PS: I referred some links online but that does not help much - Spring Data REST - PUT request does not work properly since v.2.5.7