Wicket error page runs twice

I have a requirement that when certain kinds of exceptions are thrown, I want
to customize my exception error page. I stuffed the exception into the
requestcycle and retrieve it in the page like so:

Exception exception =
getRequestCycle().getMetaData(ESPApplication.EXCEPTION_KEY);

I watch through breakpoints or log statements and the exception is provided
the first time through, but after it processes it, the error page runs a
second time, this time with a null in that value. the result is that my
error page is not getting what it needs, and renders without the needed
info.

Why would the error page run twice? I don't see any additional exceptions
in the log, and the error page does render...it just renders as if the
exception object were null.