Questionnaire (plugin)

Has anyone else had any problems when copying questionnaires with Rate (scale 1..5) questions? I can see that sometimes Possible answers -order changes randomly. Here's how I tested this:

1. I create a new questionnaire
2. I add one Rate question with Possible answers (the diaeresis ä is there on purpose):
   Math
   English
   Chemistry
   4=very easy
   3=easy
   2=hard
   1=very härd
   
3. on the course page I duplicate the questionnaire
4. I go and see the setting for the question of the copied questionnaire
   -> sometimes everything is fine BUT sometimes Possible answers have changed places e.g. like this:
   1=very härd
   2=hard
   3=easy
   4=very easy
   Chemistry
   Math
   English
   

We have Moodle 2.7.7 but what's weird is that there is no similar problem in my test environment with same Moodle and Questionnaire versions.

When copying template courses this is a big problem with reporting etc.

Could the problem be scandinavian letters äöå?