The npns in your schematic are backwards so it is going to do something weird. Other than that, there is nothing wrong with the topology.
1.125 V seems a little low. If properly designed, the "magic" voltage should not depend the the bipolar ration (1:8 or 1:16, etc). It will, however, depend on the temp-co of the resistor. If it isn't that, there is probably something wrong in your circuit. Things that could affect the results:
1) The mirror ratio of the rightmost and 2nd from the rightmost PMOS devices is not EXACTLY 1.
2) Your startup circuit isn't shutting completely off.
3) Your bipolars are biased at too high or too low a current density.
Your Vout vs temp curve should be parabolic with the voltages at -55 and 125C about 4 mV lower than the value at 30C. If it looks different you probably have something biased incorrectly. If you can't figure it out, post the Vout vs Temp curve and how much current you have in each leg.