If you'd look at the documents filed in the Celsius bankruptcy, you'd see a sworn affidavit that says Celsius stopped providing additional collateral in May 2022:
https://storage.courtlistener.com/recap/gov.uscourts.nysb.31...
>In May and June 2022, Celsius made the difficult decision to forgo providing one of its lenders, Tether, issuer of USDT, a stablecoin, additional collateral and agreed to an orderly liquidation of its loan. During the market crash, Tether issued a margin call to Celsius with regard to an outstanding $841 million USDT loan. Although Celsius had always provided sufficient collateral to support its loan, and had never previously been liquidated by Tether, the Company agreed to an orderly liquidation and settlement of its loan with Tether to preserve the remaining collateral in excess of the value of the loan
Bitcoin dropped around 30% in May-June, so this timeline lines up exactly with the 130% collateralization ratio.