The condition in visitUUIDConstructor is always true and make it return a UUID_LEGACY regardless of the uuidConstructorName

{{ BsonBinarySubType subType = BsonBinarySubType.UUID_STANDARD;
if (!"UUID".equals(uuidConstructorName) || !"GUID".equals(uuidConstructorName)) {
subType = BsonBinarySubType.UUID_LEGACY;
}}}

{{}}

Fix: https://github.com/mongodb/mongo-java-driver/pull/556

This is not present in 4.1.x as Legacy support has been dropped.