i solved this by setting the expiry time on all my headers to +1h. 
print $cgi->header(expires => '+1h');

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Originally posted as a Categorized Answer.

In reply to Re: Why does back-buttoning to a cgi script-output page yield 'Page expired'? by DarkSniper
in thread Why does back-buttoning to a cgi script-output page yield 'Page expired'? by dyfn

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