Whilst that story element did irk me a little, I let it slip because, in fairness, Wuk Lamat knew Zoraal Ja pretty much all her life and certainly knew him - as a person - far better than the Warrior of Light could have.
No - it was the final battle that really annoyed me as there was no such excuse there. She didn't know Sphene any better than the Warrior of Light did.
Wuk Lamat's interference in that fight was inexcusable and completely unnecessary. Queen Eternal outright said that the Warrior of Light was the "single greatest threat" - as should be the case. And this worked really well - it made sense and put the WoL back in the spotlight! Fighting the big-bad is what the WoL does best and the first segment of the Trial was fantastic. And then Wuk Lamat gatecrashes the fight and makes herself the single greatest threat. This was the single greatest insult the writers could've presented us with in my opinion; it undermined the Warrior of Light's significance. And so far as I am concerned she didn't do or say anything that couldn't have happened without her direct involvement!