Glad to hear users agree on with my supposition of possible game engine item creation bug/feature/game code logic and misluck from OP along with other suggestions.
Next time I spot a mine being blown up over my vehicles creating some friendly fire damage, I'll keep track of a video and report on it.
When a mine explodes under your vehicle/infantry when they are under fire from artillery or tank shells, there is really no mystery. The AOE of the shell destroys the mine, it explodes. It happens fairly often.
What is weird in this video is that small arms fire does not have AOE (or scatter), making the cause of the explosion ambiguous, and potentially related to the so called 'focus fire' mechanic.