Many to many self referencing entity showing data for one side only

I have a many to many self referencing entity. Student <-> Siblings

The issue is if I add Jack as first student and then Katie as second one and add Jack as Katie’s sibling, Jack appears in Katie’s siblings table but Katie is not in displayed in Jack’s siblings table. Would I have to create a link table in order to make this work?

Can you show your entity code, how you specify reference attributes in the Student entity?

Of course there should be a link table for many-to-many relationship.
Look examples in the internet, e.g.: Hibernate Self Join Annotation Many to Many mapping example