Any zombies killed by the Mysterious Stranger trait will be out of sync for other clients in the server and will shortly disappear from existence after 'dying'.

In the perspective of other players, the zombie 'killed' by the trait will simply be alive and will still be standing or attacking the player but will shortly disappear. Meanwhile in the perspective of the player, the zombie will fall to the ground as if knocked down but it will still be alive will be unable to be hit before shortly disappearing.

Not a major issue but strange behavior indeed.