Microsoft has now posted an acknowledgement of this issue here:
https://learn.microsoft.com/en-us/windows/release-health/status-windows-11-24H2#3652msgdesc

They are working on a fix and have a known issue rollback available for organizations that have a support contract. They don't specifically mention UAC Patching or whether existing patches built with the same cert will work as before nor do they give a specific timeframe when more information will be available.