recaptcha is not loading in Drupal 8 modal popup

I have created a email share form by custom module and added recaptach to the form. When I try to show form in modal popup recaptach will not show up. I using recaptcha(captcha_type' => 'recaptcha/reCAPTCHA) type image. If I use Math type captach('#captcha_type' => 'captcha/Math',) it will work in popup

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Could you please help me ?