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I tried to reproduce this issue, But unable to reproduce.
Steps that I have been followed.
Step1. Setup Drupal8.9.8 site through composer.
Step2. Install recaptcha 8.x-3.0 module through composer.
Step3. Register on recaptcha and created Site key and Secret key(baseurl/admin/config/people/captcha/recaptcha)
Step4. Enabled recaptcha for 'user_login_form' from here (baseurl/admin/config/people/captcha/captcha-points)
Step5. Visited the login page and I got CAPTCHA field below the password field.
I have tried to login with recaptcha module, I am not getting any error.

I have tried to reproduce this issue, But I am unable to reproduce.
Step1. Setup Drupal8.9.8 site through composer.
Step2. Install recaptcha 8.x-3.0 module through composer.
Step3. Register on recaptcha and created Site key and Secret key(admin/config/people/captcha/recaptcha)
Step4. Enable recaptcha for 'user_login_form' from here (admin/config/people/captcha/captcha-points)
Step5. Visited on the login page and I got CAPTCHA field below the password field.

Can you please provide more details so I can debug.

No details provided that would make it possible to fix this.

This is a known issue.
See the solution at the following link:
https://www.drupal.org/project/recaptcha/issues/3168481 →