OnePlus fixed that nasty bug that rebooted your OnePlus 5 when you called an emergency number, but just what caused it, exactly? The company has offered an explanation... and it's a thorny issue. Apparently, there was a cellular modem memory usage problem that kicked in when you made an emergency call while on a voice over LTE network, invoking the OTDOA (Observed Time Difference of Arrival) protocol used for positioning in an emergency. It only occurred on some OnePlus 5 units, but it was tricky enough that the company worked with Qualcomm to eliminate the glitch on devices around the world.
It's safe to say the bug should never have existed in the first place, but the transparency is important. Most companies offer little to no explanation for software bugs, and the conversation usually stops once the patch arrives. While posts like this won't offer much consolation if you're affected, they'll at least help you understand what went wrong and give you a better understanding of the bug-fixing process.