Server issues after switching to PHP-FPM (no replies)

My server was running great for years before I switched PHP execution from mod_php in apache (with an nginx reverse proxy) to PHP-FPM in nginx. My website itself doesn't use PHP except for tracking visitors via piwik/piwik.php. Since making the switch, my website monitor has been reporting some very short periods of downtime.

Could PHP-FPM be having intermittent issues executing piwik/piwik.php?