Some of the Instanced Static Meshes could not accept Hit EVENT

I have create a BP which include a Instanced Static Mesh Componet.And I add some Instance to it.Then In the Level I have Spawned couple of this Class. And I use Get Hit Result Under Finger to Select a Instance and Destroy. The Most of the Instances were HIT correctly but the rest not accept HIT EVENT.Dose someone know what’s goging on?
TKS.

ps:I also tryed Add Touch/Click Event to the Actor.Same problem.