it's the AIs fault for not being good enough to hide it.
"if that choice hurt your experience, the fault is not in the tool. It is in our own shortcomings."
The director literally outright says it's their fault for using the tool.
And what do you mean "got caught"? It's very obvious. They mistakenly thought most audiences would enjoy it, not that audiences wouldn't notice. Which makes sense given the overwhelming difference in the perception of AI between SK and the West. He even outright says he expected people to notice: "I expected some of you would be disappointed by our use of AI. I did not expect it to become this big."