java.lang.IllegalStateException encountered when saving in an entity with FetchType.LAZY

I have this entity that have these properties

@Entity
@IdClass(LockKeyId::class)
@Table(name = "lock_keys",
        uniqueConstraints = [
        UniqueConstraint(columnNames = arrayOf("lock_id", "key_id"))
        ]
)
open class LockKey
{
    @Id
    @ManyToOne(fetch = FetchType.LAZY, cascade = [CascadeType.ALL])
    @JoinColumn(name = "lock_id")
    @JsonIgnore
    lateinit var lock: Lock

    @Id
    @ManyToOne(fetch = FetchType.LAZY, cascade = [CascadeType.ALL])
    @JoinColumn(name = "key_id")
    @JsonIgnore
    lateinit var key: Key
}

then in my @IdClass

open class LockKeyId: Serializable {
    lateinit var lock: Lock

    lateinit  var key: Key

    override fun equals(other: Any?): Boolean
    {
        if (other == null) return false
  

  return (other is LockKeyId) && other.lock == this.lock && other.key == this.key
}

} When I create a new LockKey I get this error

(newLockKey is with type Key)

 var lockKey = LockKey()
 lockKey.lock = lock
 lockKey.key = key

Failed to convert property value of type 'java.util.UUID' to required type 'lock.http.model.Lock' for property 'lock'; nested exception is java.lang.IllegalStateException: Cannot convert value of type 'java.util.UUID' to required type 'lock.http.model.Lock' for property 'lock': no matching editors or conversion strategy found

I'm not sure how to fix this.

Thank you!