Really… i’ve tested I already would expect something like that
that was because I suggested you to disable headless mode and captcha solution, if you do it will see if click is working correctly or not.
That has happened to me, I was going crazy thinking that click function has a problem 
I mean, all sites now will have some kind of a protection to difficult your captcha bypass.
It can be a different way to submit the form, or a validation, or a token, a call back
I’m also new on OB2, although I have had success with some captchas recently still a challenge trigger some validations or tricks
In your case, take a look what I’ve found:
<form class="m-t" role="form" action="/login/" method="post">
<input type="hidden" name="csrfmiddlewaretoken" value="5DLskHK2g0K13fCVJJLmh4inwAQ65deNBWse7bGN7HeZRrpssHhXfDrQqIE4cx7U">
<input type="hidden" name="next" value="">
<input id="a" name="a" type="hidden" value="686e9f756df90563d775caf7df76375550e1781e60d725365a74d585a2734062">
<div class="form-group">
<input type="text" id="b" name="username" class="form-control" placeholder="Username/Email" value="" required="">
</div>
<div class="form-group">
<input type="password" name="password" class="form-control" placeholder="Password" required="">
</div>
<script src="https://www.google.com/recaptcha/api.js"></script>
<script type="text/javascript">
// Submit function to be called, after reCAPTCHA was successful.
var onSubmit_d0bd61e8dec94cb29199f9de92d0eb51 = function(token) {
console.log("reCAPTCHA validated for 'data-widget-uuid=\"d0bd61e8dec94cb29199f9de92d0eb51\"'. Submitting form...")
document.querySelector('.g-recaptcha[data-widget-uuid="d0bd61e8dec94cb29199f9de92d0eb51"]').closest('form').submit();
};
// Helper function to prevent form submission and execute verification.
var verifyCaptcha_d0bd61e8dec94cb29199f9de92d0eb51 = function(e) {
e.preventDefault();
grecaptcha.execute();
};
// Bind the helper function to the form submit action.
document.addEventListener( 'DOMContentLoaded', function () {
var element = document.querySelector('.g-recaptcha[data-widget-uuid="d0bd61e8dec94cb29199f9de92d0eb51"]');
element.closest('form').addEventListener('submit', verifyCaptcha_d0bd61e8dec94cb29199f9de92d0eb51);
});
</script>
<div class="g-recaptcha" data-badge="inline" data-sitekey="6LeHZ6UUAAAAAKat_YS--O2tj_by3gv3r_l03j9d" required="" id="id_captcha" data-widget-uuid="d0bd61e8dec94cb29199f9de92d0eb51" data-callback="onSubmit_d0bd61e8dec94cb29199f9de92d0eb51" data-size="invisible"><div class="grecaptcha-badge" data-style="inline" style="width: 256px; height: 60px; position: fixed; visibility: hidden; display: block; transition: right 0.3s ease 0s; bottom: 14px; right: -186px; box-shadow: gray 0px 0px 5px; border-radius: 2px; overflow: hidden;"><div class="grecaptcha-logo"><iframe title="reCAPTCHA" src="https://www.google.com/recaptcha/api2/anchor?ar=1&k=6LeHZ6UUAAAAAKat_YS--O2tj_by3gv3r_l03j9d&co=aHR0cHM6Ly9wcm94eS53ZWJzaGFyZS5pbzo0NDM.&hl=pt-BR&v=TbD3vPFlUWKZD-9L4ZxB0HJI&size=invisible&badge=inline&cb=i3lbizu0h81w" width="256" height="60" role="presentation" name="a-eyrz1nhrhoj2" frameborder="0" scrolling="no" sandbox="allow-forms allow-popups allow-same-origin allow-scripts allow-top-navigation allow-modals allow-popups-to-escape-sandbox"></iframe></div><div class="grecaptcha-error"></div><textarea id="g-recaptcha-response" name="g-recaptcha-response" class="g-recaptcha-response" style="width: 250px; height: 40px; border: 1px solid rgb(193, 193, 193); margin: 10px 25px; padding: 0px; resize: none; display: none;"></textarea></div><iframe style="display: none;"></iframe></div>
<div class="form-group">
<button type="submit" class="btn btn-primary block full-width m-b disabled" data-loading-text="Logging in ..." disabled="">Logging in ...</button>
</div>
I don’t know your javascript knoweldge level but mine is low :\ in curl and php more I can be more useful. But we still can test and try, it worths
I mean, in theory you should trigger manually the “thing” that will validate your captcha on submit
I have a guesse, maybe you should do this manually:
// Submit function to be called, after reCAPTCHA was successful.
// Helper function to prevent form submission and execute verification.
// Bind the helper function to the form submit action.
Even if I’m right, I don’t know if I can formulate an expression for you with working guarantees but maybe if you execute this on JS blocks you can submit the form
document.querySelector('.g-recaptcha[data-widget-uuid="d0bd61e8dec94cb29199f9de92d0eb51"]').closest('form').submit();
document.querySelector('.g-recaptcha[data-widget-uuid="d0bd61e8dec94cb29199f9de92d0eb51"]'); element.closest('form').addEventListener('submit', verifyCaptcha_d0bd61e8dec94cb29199f9de92d0eb51);
Is a good way make use of console tab on your browser developer tool, you can run your config in debug mode with no headless mode, when browser opens, open console wait puppeteer get recaptcha solution and test your expressions
In console, while you are typing stay tuned for the preview of your expression result, so in many times before you finish typing the expression on console if u see something wrong can waste less time and test faster
After this, if still not submiting need verify if is missing some token or any else
Let’s see if anyone else takes a look around here to help