The 3 others Dead Robot Dogs are away

I have found another Problem with the Robot Dogs, see Picture, i have killed the Tank, but i have also killed the 4 Robot Dogs that near him, but see at the Picture? it is about 1 Robot dog dead? Where the other 3 there i habe bevor killed? She lies all four dead on the Ground after i have killed the Tank, the 3 other Robot Dogs are away from the ground, after he´s lying on the ground dead!!! That i mean at my problem with the Robot Dogs, when he killed, first they are dead, then immediately disappeared from the Game, which is not normal, because there should be 4 dogs on the meadow, there were only 4 but now only one