As I said, it looks like them but I can't be 100 sure that they are behind Upwork bumping but in the end it doesn't matter much who exactly is doing that.
Exactly. It doesn't matter who does this, but it is important to identify and publicly denounce those projects. This is not marketing, but a scammy behavior, and no serious project is going to act like that.
It's just as bad as plagiarizing a white paper or having a fake project team. It's really good that you keep this topic up to date.