Right right, but this was advertising language. In reality it was a one-time performance bonus, but they called it a signing bonus to trick people into joining.
The problem ICE lawyers will have is that if they call it a signing bonus, maybe the fine print doesn't matter, because people reasonably believed that it was one... So my prediction is a class action lawsuit. Although that will be interesting because there are limits on what federal employees can sue for. We shall see.