Get this...I start the server in php5 and a specific HTML element ('a' element with a background image) is nowhere to be seen, I reboot the server in php4 and the HTML element is displaying properly. I boot back and forth between php5 and php4 with absolute consistent results, not displaying in php5 and displaying in php4.

The thing that blows my mind is that:

• the HTML is consistent between boots of php5/4, so both scenarios have the necessary HTML elements
• the CSS is consistent between boots of php5/4, so both scenarios have the necessary CSS definitions
• there is an identically styled sibling element, with different class name that displays properly
• the problem is reproducible between browsers, between platforms. I've tested it on every possible config, Mac/Windows, IE6,7,8, FireFox, Safari etc... When the server is booted in php5 there is one HTML element that just doesn't display/render.

A stab in the dark, I turned on PHP error reporting in php5 (to see if there would be any clues there) and low and behold the HTML element is now rendering in php5. I turn off PHP error reporting, and restart php5 and the HTML element is still rendering in php5, and the problem has been fixed...and I can't get the problem to reproduce.

This is why my curiosity has brought me here. I just spent about four hours scratching my head trying to figure out how this could be. And now, I ask any php web dev gurus out there...what the heck was this all about?