I recently switched my web server to Centos 6.3, with apache 2.2.15, PHP 5.4.11 and APC 3.1.14.
From time to time I have received complaints from clients that the page is not working, or strange errors appear. I saw that the affected pages have question marks and other strange characters in random places on the output, although the sources are fine. When I change one letter in the source file, the page starts working fine.
I suspect APC, but I cannot find clues when and why this happens.
I use mercurial to push changes to production, but I have used this approach for years without any problems. Something in the configuration may be new now, but unfortunately, I am not keeping my previous configuration.
Below is a screenshot of the last damage.
: , , , ( , - - APC):
, , 100% , . 111 . , ...