%env(bool:FTP_ACTIVE)% should be considered as a bool but it's considered as a string.

I end up with error like

Parameter #1 $ftp of method App\Core\Service\Logistic\Reflex\ReflexFile::setFtp() expects bool, string given.

Currently, the value is inferred with the code

if ($parameterKey !== null) {
    $parameter = $this->parameterMap->getParameter($parameterKey);
    if ($parameter !== null) {
        return $this->generalizeType($scope->getTypeFromValue($parameter->getValue()));
     }
}

There is a lot of env var processor: https://symfony.com/doc/current/configuration/env_var_processors.html

I can contribute, but how you do you want to handle this @ondrejmirtes ?
Should I check if the value start with %env(bool, ..., to consider this as a special case ?