Same here.
This appears to be since I’ve updated to the latest version today.
Going in Debug mode with IE11
If I open a Page, I can modify the English (primary language) and hit Update button.
But if I click on the second language tab I get an error in post.php for this line:
document.getElementById('ppqtrans_select_'+ppqtrans_get_active_language()).className='wp-switch-editor';
Error is:
Unable to set property 'className' of undefined or null reference