Encoding problem

Hello.
I’m having a problem with encoding, more precisely, with letters “? ? ? ? ?” on my wordpress website.

Now, heres that problem in more details:

– It is showing those letters, but they are thicker/thiner than other letters.

– I dont think it’s theme problem, because I’ve tried other theme (at least on live preview) and it looks the same.

– And here’s the part that’s really weird, at least for me : When I’m loged in on my website, and in other tab I open any page, article or whatever, letters look great, like there’s no problem at all.
But as soon as I logout, letters go back to same problem.

– When installing wordpress I’ve set it UTF-8, and I’ve just checked MySql and it says UTF-8 too (general_ci).

– I didn’t change anything, so there’s no way I could mess it up somehow.

– Only thing that I’ve tried was adding some other font from google.com/fonts, but that didnt solve this problem.

I’m not really that good with all this, so please if you have any sugestion, solution or anything to say about this problem, just keep it simple.
Thanks in advance.