We only started shipping Yubikeys with version 5.7 so it's probably low likelihood someone brought their own 5.5 device.
Casa recently added yubikey support.
https://blog.casa.io/secure-your-bitcoin-with-yubikey/
Casa supports firmware versions >= 5.5. This vulnerability exists for firmware versions < 5.7. Install Yubikey Manager to check your firmware version.
We only started shipping Yubikeys with version 5.7 so it's probably low likelihood someone brought their own 5.5 device.