If it is fake then it certainly has been repeated a few places.
The rumor is 180000 wafers for GPU next year, which is impossibly large. In comparison, AMD book 200000 wafers for all of their CPU, GPU, and PS5/XBOX cpu.
Maybe they can't do anything about it. I admit my knowledge of finance is limited. I've read about the SEC doing investigations after Elon Musk tweet for example.
But I do understand your cynicism on Taiwanese media. From the PTT link, I see one comment says,
> 現在放消息都會被當出貨文.....
Which translate to: Right now, whatever the news leak says, it's all believed [by people] to be a pump-and-dump story.