Have you enrolled fingerprints with the reader on another OS before? The reader saves them locally, so you might have to delete the old ones first. There is a python script for that, I’ll update my reply when I found it.
UPDATE: script can be found here: https://github.com/lightrush/framework-laptop-formula/blob/main/framework-laptop/files/fingerprint-reader/libfprint_delete_device_prints.py
or here: Fingerprints not getting deleted from device? (#415) · Issues · libfprint / libfprint · GitLab