Notably, this device-linking concept of operations has proven to be a low-signature form of initial access due to the lack of centralized, technology-driven detections and defenses that can be used to monitor for account compromise via newly linked devices; when successful, there is a high risk that a compromise can go unnoticed for extended periods of time.
Well, hopefully that gets fixed soon.
I saw elsewhere that Signal has already addressed this problem and issued an update. If your app is up to date as of now, you should be good to go.