V1 motion sensors and contact sensors have the same problem you mentioned. And unfortunately the v2 sensors have what appears to be the same hardware design other than the power supply being modified to use AAA batteries, so they may be susceptible to the same issue.
The V2 sensors no longer use button cell batteries, so their battery life is much longer. I have had one V2 motion sensor and two V2 contact sensors in service for over three years (and many others in service for less time than that), and they are all still working on their original batteries. One of my V2 sensors just reported low battery for the first time about a month ago, but the battery level has read “normal” ever since with no more low battery warnings. But I am definitely concerned about premature death if the batteries ever do die.
Regarding the fact that the battery voltage was 3V on your failed device, those button cell batteries will often read a normal voltage when tested with a volt meter, but even the slightest power draw will cause the actual voltage to drop significantly. I experienced that phenomenon many, many times when trying to figure out what was going on with my huge collection of v1 sensors. Put a 35mA load on the battery (similar to the bootup power draw) when you’re measuring the voltage with a meter, and the voltage will drop well below the 2.7V needed to keep the motion sensor working properly. And when that happens, the MAC address problem you experienced can occur. A horrible design.