Symfony version(s) affected: Symfony 4.4, but it seems to be the same on 5.* also.

Description
Seems to be a bug for some of the form templates for choice field with expanded and multiple settings set to true.

What I want is to add css class to label of choice class but not the choices. I add 'label_attr' => ['class' => 'red'] as I would to any field. And it actualy works if I set expanded to false.

It seems all bootstrap templates suffer from same problem but not div and table templates.

It this a bug in bootstrap templates?

ChoiceType::class,
[
    'choices' => ['choice must be black' => 'test'],
    'label' => 'label must be red because of css class',
    'label_attr' => ['class' => 'red'],
    'multiple' => true,
    'expanded' => true,
]

How to reproduce

git clone https://github.com/aurelijusrozenas/sf-form-choice-template-bug.git
cd sf-form-choice-template-bug
composer install
symfony serve