Linux login always reported as “suspicious”

Since 2FA has been made available (but not enabled for admin logins yet on my site) Wordfence reports admin logins from my Linux laptop (Debian 9.9 – current) as “The request was flagged as suspicious” and sends an admin email “Login Verification Required”.
On the same network, same login, my Windows7 box doesn’t do this.
Google reCAPTCHA v3 is enabled
It’s unclear why the behaviour is different and this is creating delays.
What can I do to stop Linux logins (likely more secure than Windows) being flagged?

Thanks