Last year, EOTech had to admit some serious problem with thermal drift. Trijicon quietly addressed the issue to some customers regarding MRO.
In short, the drift was less than 1.9MOA from -51C to +71C, with one single sample going 2.2 MOA. The shift in position after temperature change from ambient to extreme, then back to ambient was 1.1 MOA on average.
From: Soldier Systems