When macOS Monterey was rolled out, an issue arose whereby some Macs with T2 chips were bricking. 9to5Mac reports that this has now been resolved.
Now, Apple says it has identified an issue affecting the T2 security chip that caused this problem and is rolling out a fix to prevent it from happening in the future. In a statement, Apple explained (via Rene Ritchie): We have identified and fixed an issue with the firmware on the Apple T2 security chip that prevented a very small number of users from booting up their Mac after updating macOS. The updated firmware is now included with the existing macOS updates. Any users impacted by this issue can contact Apple Support for assistance. To prevent this problem from occurring to additional users, Apple has rolled out an updated version of the bridgeOS firmware that runs on the T2 security chip. Users already impacted by the problem are instructed to contact Apple Support for assistance.