Page Template doesn't change

Dear Chouby,

after updating wordpress to 4.4.2 I noticed the following problem: I cannot change the themes template, after each saving the page it switches back to default page template.

I tested this issue in my own theme (wp-bootstrapmaster childtheme) and also in twenty-fourteen. Both online and local on my testserver ….
I also deactivated all plugins , except for the polylang plugin (version 1.8.1).
When I deactive polylang I can change my page template as ususal.

Every advice would be great, your plugin is essential for us for having a fully working webpage (http://www.spraachen.org)

Regards

chillinhen

https://ww.wp.xz.cn/plugins/polylang/