[SpicyLemonZest]

These reports are not full audits, although Tether would certainly like us to think they are! If you click into one of the reports, the auditors list the steps they took, and they're focused almost entirely on verifying the existence of Tether's self-reported assets on the report date. They would not, for example, have uncovered an FTX-style "hidden, poorly internally labeled fiat@ account" by following these procedures.

You'll also note that they're following the "International Standard on Assurance Engagements 300 (Revised) ~ Assurance Engagements Other than Audits or Reviews of Historical Financial Information", which heavily suggests that this is not an audit and they did not review historical financial information.