While the problem is more general, the nature of the problem suggests that it is triggered by an event, or an accumulation or sequence of events. A script may or may not be triggering the problem, but determining or eliminating this possibility is a step toward resolution.

Could a particular execution path in a script change something in the environment? Could it trigger a bug in Apache? Could a bug in an XS module overwrite some memory location that it shouldn't? Could the problem be related to POST or GET parameters sent to a script? Maybe.