ADA4522 work for ref voltage

HI,

Now we use ADA4522 OP Amp and LM385-2.5 ref voltage to make 0.9 reference voltage, work voltage is +/-5V. Now the question is that, sometimes output 0.9V, sometimes output 4.9V when power up. So I use LT1366 to replace it, output always is 0.9V each power up. I can't understand why, also I want use ADA4522 for zero drift performance.