No, Tether never completed an audit. Their auditor fired them. Their claimed "frequent professional audits" on the home page encompasses precisely zero completed audits.
https://www.coindesk.com/tether-confirms-relationship-audito...
> Given the excruciatingly detailed procedures Friedman was undertaking for the relatively simple balance sheet of Tether, it became clear that an audit would be unattainable in a reasonable time frame. As Tether is the first company in the space to undergo this process and pursue this level of transparency, there is no precedent set to guide the process nor any benchmark against which to measure its success.