Strange characters only in menu

What do you mean by go weird? Can you provide a screenshot?

?????? shows like very strange characters.
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Have you tried deactivating all of your plugins and switching to the default Twenty Fifteen theme?

Yes i tried, same thing. Post content work normally, just menu is problem. When I do not select menu location and wordpress automatically add pages in menu, everything is OK and characters shows nice.

So the problem is still happening with the Twenty Fifteen theme?

Yes,is still happening with the Twenty Fifteen theme. ??
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What translation are you using on your blog?

No translation, just uncoding characters utf8 general_ci

No I mean is your blog in English, German, Dutch, French etc.

Croatian

Is it messing it up if you change it to English?

Yes, I tried it, does not help

Have you tried re-installing WordPress 4.3? Just go to the Dashboard > Updates and click re-install.

Also tried, no luck for me..

Tried to reinstall again, nothing happens..