Red velvets song stolen?

I'm watching the first episode of your last solo on Netflix and all of a sudden the song by Irene and Seulgi, Monster, comes up first

Not with their voices, but in English from someone else.

Can you do that? Because in principle it's a cover and you always use the original music of the singers.

Yes. The singer is a different one. Probably the producer didn't get the rights to this song and that's why he did it that way.