Does this count?

Valisiel leaps from hiding to attack!
Valisiel swings an enruned black rolaren warblade at a Grimswarm orc warlock!
AS: +204 vs DS: +92 with AvD: +35 + d100 roll: +94 = +241
... and hits for 103 points of damage!
Powerful slash!
The orc warlock's right leg is severed at the knee!
A Grimswarm orc warlock falls to the ground grasping his mangled right leg!
The orc warlock is stunned!
A dark shadowy tendril rises up from a Grimswarm orc warlock, writhes its way up an enruned black rolaren warblade towards Valisiel and lashes out malevolently...
Valisiel blinks and appears distracted.
Valisiel swings a blackened vultite gladius at a Grimswarm orc warlock!
AS: +179 vs DS: +36 with AvD: +40 + d100 roll: +65 = +248
... and hits for 72 points of damage!
The orc warlock is backed up by a strong slash to his abdomen!
A dark shadowy tendril rises up from a Grimswarm orc warlock, writhes its way up a silver-runed blackened vultite gladius towards Valisiel and lashes out malevolently...
Valisiel blinks and appears distracted.

You hear a crackling sound from a Grimswarm orc warlock as shadowy ether begins swirling wildly around her.

A Grimswarm orc warlock appears to have sustained massive amounts of system shock!
... 675 points of damage!
Powerful blast reduces the orc warlock to a smoldering pile of ash!
The orc warlock rolls over and dies.
The silvery luminescence fades from around a Grimswarm orc warlock.
The powerful look leaves a Grimswarm orc warlock.
The bright luminescence fades from around a Grimswarm orc warlock.
A shadow seems to detach itself from a Grimswarm orc warlock, swiftly dissipating into the air.

If that clip hasn't been edited its a bug. 712 shouldn't turn on caster in those circumstances.

Attacker is dual wielding; he scored two different hits, one with each weapon. Wouldn't that trigger two retribution attempts?

It was changed. Its one every hit now (there are two retaliations in the clip before the cloak turns on the caster). Which gets pretty obnoxious with some retaliation spells (e.g. dispel) though its irrelevant a lot of the time.

Huh, I was under the impression it did the murderous backlash only in specific/weird situations, like if the caster had a spell prepped or something. But that's obviously not the case here.