Can't delete sessions due to foreign key constraint violation

org.springframework.dao.DataIntegrityViolationException: Hibernate operation: could not delete: com.atlassian.confluence.labels.Label#2031993; SQL []; ERROR: update or delete on table "label" violates foreign key constraint "fk594acc827072aef" on table "notifications"
Detail: Key (labelid)=(2031993) is still referenced from table "notifications".; nested exception is org.postgresql.util.PSQLException: ERROR: update or delete on table "label" violates foreign key constraint "fk594acc827072aef" on table "notifications"
Detail: Key (labelid)=(2031993) is still referenced from table "notifications".
at org.springframework.jdbc.support.SQLStateSQLExceptionTranslator.doTranslate(SQLStateSQLExceptionTranslator.java:100)
at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:72)
at org.springframework.orm.hibernate.HibernateAccessor.convertJdbcAccessException(HibernateAccessor.java:364)
at org.springframework.orm.hibernate.HibernateAccessor.convertHibernateAccessException(HibernateAccessor.java:351)
at org.springframework.orm.hibernate.HibernateTemplate.execute(HibernateTemplate.java:375)
at org.springframework.orm.hibernate.HibernateTemplate.execute(HibernateTemplate.java:337)
at com.atlassian.confluence.labels.persistence.dao.hibernate.HibernateLabelDao.findByLabel(HibernateLabelDao.java:117)
at com.atlassian.confluence.labels.DefaultLabelManager.getLabel(DefaultLabelManager.java:623)
at com.atlassian.confluence.labels.DefaultLabelManager.deleteLabel(DefaultLabelManager.java:561)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
...