<?
function foo() {
}

foo();

echo( "Hello world!" );
?>

This small script randomly produces the following fatal error:

Fatal error: Call to unsupported or undefined function foo() in /xxx/xxx/foo.phtml on line 5.

NOTE: The longer the foo()'s boody is, the more often the bug occurs. We have been encountered this problem also with previous PHP version, but less frequently (not enough to be serously taken into consideration).

Our config:
configure --disable-safe-mode  --enable-memory-limit  --enable-track-vars   --enable-force-cgi-redirect --enable-discard-path  --with-config-file-path=/usr/local/etc ${MYSQL} --with-gd  --with-xml --with-apxs=`find /usr/local/${VERSION}/ -name apxs -print`

We run PHP as an Apache module with error_reporting set to level 15.

Related problem: when the parser finds a real syntax error, reloading the broken page often produces the same kind of fatal error (rather than issuing again the syntax error). Looks like the parser got some junk from its previous file rendering (?).