doubled text aricle in content area

My problem generally concerns all Gavick templates (I tried some of them: postnote,blac&white, pixellove) and not the non-Gavic templates. The problem is a doubled article text in content area. You can see how it looks at our temporary sites: http://www.li-der.pl and http://www.poliglot.linuxpl.info. It appears when you are switching second or other time the same article in short period of time. See also attached printscreen. Could you please suggest any solution of that problem?

Hi

Till now I've seen 2 cases with this problem:

1. Solution was a PHP version update (user was running 5.2.9)

2. Problem was caused by joomla progressive cache, I adviced to disable it and use GK Cache instead.