It has been found out previously that its much more common for unrelated mobile devices of the same model to have exactly same fingerprint than for desktop devices. This happens because mobile browsers are sandboxed and there are not enough variables to reliably fingerprint the device.
To mitigate large amount of duplicate browser false positives, mobile browsers fingerprints are now ignored. Persistent Device ID cookies will continue to be used to detect duplicate accounts on mobile devices.
DupZapper does not use mobile device fingerprint for raising alerts by default. This behaviour can be changed in settings.