The technical report demonstrates the latest 4E71 firmware for AirPods Max indeed reduces the ANC and it’s not just in peoples’ heads. At the time of this writing, Apple hasn’t yet addressed RTings’ findings. There’s no class action lawsuit, though some believe it could happen. There is, however, an ongoing lawsuit between Apple and Jawbone Innovations claiming that Apple infringed on its noise cancellation patents, as discovered by Reddit user u/facingcondor.
If Apple thinks it’s a real issue, it could do a recall, or more likely, fix the ANC reduction problem in a future firmware update.