It's just an AD. Completely normal on a new and complicated type.
Please note that if it was serious enough to put them all on the ground, the FAA as the original issuer of the type certificate, can ground the worldwide fleet by suspending or revoking that type certificate.
EASA grounded the Dassault Falcon 7X worldwide last year (at the request of the manufacturer) by doing exactly that.
Its an emergency brake and it works. Once the issue is addressed, the type cert is re-instated.
But this is just an AD. Move along.