Congratulations! You now have a landmine that can be triggered by both infantry and vehicles and inflict heavy damage to both!
It is important to have a pistol on hand and to shoot the anti-tank mine once (2 blows it up) to prime it to allow for the anti-personnel mine to detonate it as it does only partial damage to a full health anti-tank mine.
That’s great! I’ll definitely memorize a few more.
There is even better trick place a lot of anti tank mines on a capture zone then call artillery when the enemy is swarming it 
It used to be possible to do this without shooting the mine once - maybe the devs didn’t like this, since AT mines deal much much bigger damage against infantry than AP mines. - so this specific thing might have been a fix for this.
That being said, the extra effort seems quite fair to be honest.