I've worked for one of those companies and I don't understand this. It was about paying them for just a test problem? During an interview presumably? And you g

I've worked for one of those companies and I don't understand this. It was about paying them for just a test problem? During an interview presumably? And you got involved with them through HR even given how completely separate they are? On the actual jobs you get so many timed tasks that a single one wouldn't even stand out, really.