What issue did Bank All Ltd. face in regard to their AML audit?

The issue faced by Bank All Ltd. regarding their AML audit revolves around the challenge of finding an audit firm due to prior engagements. This scenario highlights the complexities businesses encounter when seeking external resources for compliance and auditing functions. Banks, especially, may require specialized audit firms that understand the nuances and regulatory requirements associated with Anti-Money Laundering (AML) practices. If a firm has existing commitments or contracts with other clients, it can be challenging for another organization to secure their services, leading to potential delays or gaps in the audit process. This situation emphasizes the importance of planning and foresight in scheduling audits and engaging audit firms well in advance to avoid such conflicts in availability.

The other options might relate to various challenges institutions face, but they do not address the specific hurdle of securing an audit firm due to existing engagements, which is a critical concern for ensuring timely and effective AML compliance.