I've searched the history, and I'm not seeing this issue. When I tried to Add Smart Start Devices and scanned the QR code of the lock, I get SmartStart Warning: QR code not supported. When I add it manually as either a Kwikset 620 or a Kwikset Generic Zwave lock, it adds it as an "Aeotec Siren 6 New." I tried a different Kwikset Zwave lock, and it does the same thing.
Solution: I can go into the Device Info and manually change the Type to "Generic Z-Wave Lock" to get the basic lock/unlock commands, as well as programming lock codes working.
You can also set the type to be "Device" (which is usually considered a do-nothing driver) and then click "Get Info". Then, in the logs, a fingerprint will be output.
Swap back to your real driver and send a message to @mike.maxwell with that fingerprint. He will add it to the internal DB, distributed with the next Platform update. It won't help you directly, but it is how new devices get recognized.
The "Device" driver grew over time into something quite a handy. It has buttons to delete child devices and a few other options. Swap it in, click something useful, swap it out. Really handy.
This has historically been the correct driver for this and most other KwickSet locks. The fingerprint is close/identical to, if I remember correctly, a Schlage BE469 so that driver tends to get associated with the device and always needs to be changed.