I have mounted the chip on a breakout board.
Which package?
CERDIP8, DIP8 or SO-8?
After my experience at least the plastic DIP8 package needs many years to stabilize.
Attached the first 1500 days of 2 samples.
Between the lines of a Maxim datasheet: the stability is directly affected by the package.
(the more stiff and the larger the package the larger the stability).
On a AD586LQ reference I had good experiences with cyclically loading the 5V output with 3*1K resistors (15 mA) over night.
After some months the output stabilized.
So I would probably build a cirquit which draws 15 mA for 1.5 hours and 0 mA for 0.5 hours cyclically from the reference output.
with best regards
Andreas