Hi, I recommend that you ask your issue to author of the multi-language plugin which you use in order to check this subject in more detail. They can produce faster solutions because they are more familiar with the plugin codes.
Can you activate the default wordpress theme and check the problem so that we can understand if it is a theme-related problem? If the same problem occurs in the default wordpress theme, the problem is not caused by our theme, but by the plugin.
Thanks for your understanding.