Unfamiliar text is displayed in a language other than the one selected

While I was playing the game, the following message appeared in the chat

"你好,我係流亡者 現在我還需要500 Mirror of Kalandra 才能乘船上去打爆 超級塞勒斯. 如果你看見這個訊息,請私 擁有這物品的人,請資助他!
事成之後我將令你成為奥瑞亞的王!!!"

The speaker was not displayed, and the text was the same color as that sent from the game.

Why did this appear?

If it is a message originally registered in the game, please let me know.

If it is possible to send such messages to others, isn't this a fatal flaw?

I do not use any external tools, and the only thing I have no control over is the item filter. Does the item filter have this kind of function?

Also, if GGG has no involvement in these things and you cannot confirm whether they actually happened, I would like you to say so.

I have no intention of continuing playing a game where it is possible to illegally display chat by falsely pretending to be from the game's management.