Next I would do is wrapping tee with a shell script which traces tee, to see what it does, specifically open/closes. Log the fileno() of your STDERR and STDOUT to the apache error log (real STDERR ;-) as well as the fileno() of your redirected handles. Ah, and you could omit the close STDOUT - just re-open it. I didn't check the return value of close (shame on me) which you should do.

Could you provide a condensed version of the code you are running?

--shmem

_($_=" "x(1<<5)."?\n".q·/)Oo.  G°\        /
                              /\_¯/(q    /
----------------------------  \__(m.====·.(_("always off the crowd"))."·
");sub _{s./.($e="'Itrs `mnsgdq Gdbj O`qkdq")=~y/"-y/#-z/;$e.e && print}