Objectivity

(Please note that I do not have the text to confirm that this is what it states.)
The conceptual framework approach looks at threats to compliance with the fundamental principles generally – so not just objectivity.
Independence is not a fundamental principle but the definition of independence includes acting with integrity and exercising objectivity and professional scepticism. Failure to exercise professional scepticism could result in a lack of diligence that would be a threat to professional competence and due care.
Different threats affect different fundamental principles. For example, when we are talking about auditors and audit clients, the significance of any threats to independence has to be evaluated (because the auditor’s report in an independent auditor’s report).
Although self-interest and self-review threats threaten objectivity – they will also threaten integrity (because they threaten independence) – but they could threaten other fundamental principles also.
For example overdue fees create a self-interest threat. Performing another audit with fees outstanding could threaten professional competence if the auditor were to “cut corners” on audit work (to reduce further costs).

You are very welcome.