You are testing line of sight for 3 instances at once, if any 2 of them have each other in sight, your condition will be true.
If you need to test if left player instance sees another player instance, you need to pick left player first.
But then your event "player has line of sight to player" will not work, because "player" now refers to only 1 picked instance.
There is a workaround using a family, see this demo:
https://www.dropbox.com/s/ey9ecnpwkuhco ... .capx?dl=0