Captcha text field has different length on pop-up window and on registration page

There are 2 issues related to captcha text field length:

1. Go to main page, press "Sign Up"
Actual result: Pop-up window appears. Captcha text field has length less than the other fields

2. Go to main page, right click on "Sign Up" and choose open in new tab
Actual result: Registration page open in new tab. Captcha text field has length bigger than the other fields

Expected result: All fields have the same length in both variants