All op-amps are not created equal.

The middle stage that sums the temperature voltage with the offset=20
voltage is producing .641 V instead of .201 Volts.  Mr. Prosser is=20
correct about checking for oscillations - anytime a DC circuit looks=20
strange, this is a good idea to check with a scope (or CRO in the antipodes=
)

But this time, it is probably the '358 output stage that is doing you=20
wrong.  The offset stage is trying to get it to sink 100+ uAmps and it=20
can't do it. So it comes up out of saturation and gives you the results=20
you noted.

If you want to make it work with the '358, try adding a 470 ohm pulldown=20
to the middle stage output to ground.  It may require less than 470 to=20
get the results you want.

YMMV but this is my guess.
--=20
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