Yet another Apache 2 question

I'm currently using a PHP/Apache 2.0 (prefork) combination which seems to be running reasonably well, however I've just become familiar with the potential issues with PHP/Apache 2.0 so I intend to roll back to Apache 1.3 some time soon. I have a question about a particular error I have received with this setup: Many of the virtual hosts on my server have custom php_value settings. A user has reported that a particular error occurred in a PHP script, and the message indicated to me that the script had actually been loaded as if it were in another virtual host (ie. the specific php_value settings for the other virtual host were loaded instead). Both the user and I have never been able to replicate it and I have received no reports of similar errors. Could this be one of those unpredictable errors which the FAQ describes, or could this be attributed to some other problem? If anyone could shed some light on this it would be much appreciated! Many thanks, Duncan.