Strange behavior with Translatable::fallback(missingKeyCallback

[invaders-xx]

I use version 6.1.0 of the package and L9 (latest)
I have set the fallback within my AppServiceProvider boot as this:

Translatable::fallback(missingKeyCallback: function (
            Model  $model,
            string $translationKey,
            string $locale,
            string $fallbackTranslation,
            string $fallbackLocale,
        ) {
            if (isset($model->company_id) && $model->company_id) {
                return $model->getTranslation($translationKey, collect($model->company->languages)->first());
            }
            return $model->getTranslation($translationKey, $fallbackLocale);
        });

it works well when 'en' is set in company languages but not working when not set. Is anybody facing this behavior?
For example, if I have ['en','fr','de'] in company languages it works( it goes through the fallback function) , if I only have ['fr','de'], it does not work, the result is empty and never goes through the fallback function
my fallback_locale in config/app.php is set to 'en'