Recently for some unknown reason the cache plugin ‘Hyper Cache’ stopped working and I had to play around with the settings. After a couple of days I realize the text in the site have gone crazy.
While searching the WordPress support I found out that the solution to the problem was the configuration file "wp-config.php". When I restored the back-up of the file, the unicode start to look fine.
To troubleshot what might have happened, I removed some of the lines that were not present in the original files were and restored the new config file.
The problem were the two lines in the config file:
All I did was comment those two lines
And, the unicode started working just fine.
That was the solution that worked for me. If you face similar problems, please post if this solutions has helped you.