killing a Varient:7 horse last turns the screen red [Detailed]

What I did:
/summon EntityHorse ~ ~ ~

{Variant:7}

/kill @e[type="EntityHorse"]

What I thought would happen: The invisible horse would die

What happened: The screen turned red

How to reproduce:
/summon EntityHorse ~ ~ ~

{Variant:7}

/kill @e[type="EntityHorse"]
Do that until the screen turns red, it might have to kill some wild horses first.