Back in 2015, allegations started appearing about EOTech holographic weapon sights being susceptible to thermal drift. The military stopped fielding EOTech sights, the company starting refunding everyone who turned in their sight, and a class-action lawsuit was filed.
A few years later, the military replaced their old EOTech sights … with EOTech sights.
Thermal drift is when you sight in your optics in one temperature (say, 70 degrees) and the point of impact changes at other temperatures (such as −40 degrees) because of the sight being affected by the temperature change. This could cause your bullet to impact six inches away from where you aim at 100 yards!
All optics will exhibit a certain amount of thermal drift, and it primarily occurs at extreme temperatures. The Trijicon MRO, a red dot that competes with EOTech’s lineup for military contracts, also suffers from thermal drift. The problem can be solved with a few confirmation shots before you take your gun hunting.
As for how EOTech handled the situation, well, they freely refunded unhappy customers, settled with the government, tightened their manufacturing standards, and are still one of the best close-combat optic manufacturers today.