WebPage#onAfterRender erroneously reports missing header

In WebPage#onAfterRender() there's a check wether a header was missing on a page and header contributions would be lost.

In the following case this check erroneously barks:

• page A was requested
• in A's onBeforeRender() a RestartResponseAtInterceptPageException to page B is thrown
• page A's onAfterRender() is invoked in a finally block
• processing continues with page B

Page A's onAfterRender() complains about the missing header, althought his page was never completely rendered.

IMHO there's a check missing in WebPage#onAfterRender():

if (getRequestCycle().getResponsePage() == this)

Or is Page A not allowed to throw RestartResponseAtInterceptPageException in onBeforeRender() at all?