Not to my knownledge. Plesk is rather independent from your OS or webfiles.
Is the problem occuring on all sites/files or are these files that change permission part of a script ?
The problems looks like a cron-job of an installed php-script that running every x-hours of x-days to check if...
When I first started my VPS I suffered the same problem, and I must admit setting up the correct users/groups with their correct permissions was like going through hell.
Basicly it all comes down to install something like SUPHP (http://www.suphp.org). Without a tool like that, all users will...