Hi there,
I also scratched my head with this quite a while when I finally figured out a kind of solution. I found this file called icl.php (https://github.com/ajkovar/contact-form-7/blob/master/modules/icl.php) and when I added it to contact-form-7/modules my icl tags started to work again.
I’m grateful for Contact Form 7 and thanks for all the hard work that has been put in to it but I hope there would be another solution to make forms work in multiple languages than creating lost of different forms. And after you have created them all it’s a lot of work to make changes to them.