Session overwritten by async AJAX-calls?

I have a problem with a array stored as session variable getting overwritten if I do async AJAX-calls. Some values are saved and some are not. I tried to switch to the database-driver on Laravel 5.1 with no luck.

Is this a known fact, and I should design around it, since Laravel seems to use a custom session handling?

Found this in Github https://github.com/laravel/framework/issues/7549

Thanks in advance!

/ Jan