From the first site:

Auditor Rotation

Placing statutory restrictions on a client's ability to replace the auditor, or requiring long-term auditor appointments could reduce opinion shopping. In some Australian jurisdictions, for example, the auditor continues on an engagement until death, removal for cause, resignation, or loss of capacity to act.


From the second one:

Factors external to the audit organization may restrict the audit or interfere with an auditor's ability to form independent and objective opinions and conclusions. For example, under the following conditions, an audit may be adversely affected and an auditor may not have complete freedom to make an independent and objective judgment.


HTH
Andrea