Wouldn't it be better to check if Checkbox field is unchecked and then skip it.

Browsers process form fields in a linear fashion (that's the point of putting hidden field before checkbox).
Your patch introduces non-linear behaviour which is nothing like browser's and it will introduce a lot new bugs.

Could you check if skipping unchecked fields work?

Before:

foreach ($fields as $field) {
	if ($field instanceof FileFormField || $field->isDisabled() || !$field->hasValue()) {
	    continue;
	}
	// ...
}

After:

foreach ($fields as $field) {
	if ($field instanceof FileFormField || $field->isDisabled() || !$field->hasValue()) {
	    continue;
	}
	
	if ($field instanceof CheckboxField && $field->isChecked() === false) {
	    continue;
	}
	// ...
}

The issue is that the symfony component does not add all fields to the form... It essentially deduplicates based on name too early

Ah, it is a WONTFIX issue: symfony/symfony#11689

Yeah, so the question is do we want to work around it via the solution proposed by @SOHELAHMED7 ?

It seems that a better solution would be to stop using Symfony\Component\DomCrawler\Form, extract all fields using Crawler and do all processing in InnerBrowser code, but it is a lot of work.

So a simple fix like this will have to do for now.

@Naktibalda

Do you mean to say like this 0d03718 ?