Steps:

1. Add a new Language: German
2. Create a new User Group: Editors GER
3. Create a new Role: Editor GER with Policies:

4. Assign Editor GER Role to Editors GER User Group.
5. Create a new user in Editors GER User Group.
6. Log in to the Back Office as a previously created user.
7. Create form.
8. Add Button field.
9. Open Settings.
10. In Action field select Redirect to a content item.
11. Select content. In UDW go to Create tab.

Actual Result:
You will be presented with both the English and German language in "Select a language" field.

Expected result:
Only German Language available.