Money disappearing is a minor failure in the sense that it is easy to track. Banks do daily audits to check that money sent in one side is deposited in another.

Money disappearing is a minor failure in the sense that it is easy to track. Banks do daily audits to check that money sent in one side is deposited in another. If there is any issue, they will track it and rectify within the 3 days grace period created exactly to work around these bugs.