It looks like there is something wrong in Intl data with Symfony 3.4 because it is not in sync with Symfony 4.4 & 5.
Maybe a merge issue?

For example:

Symfony 3.4 has XA & XB countries (pseudo-accents & pseudo-bidi) which I think is a mistake:
https://github.com/symfony/symfony/blob/3.4/src/Symfony/Component/Intl/Resources/data/regions/fr.json#L250-L251

They are not included in Symfony 4.4: https://github.com/symfony/symfony/blob/4.4/src/Symfony/Component/Intl/Resources/data/regions/fr.json
Or 5.X: https://github.com/symfony/symfony/blob/5.x/src/Symfony/Component/Intl/Resources/data/regions/fr.json