So an American company (amazon) was going to buy iRobot, but that was struck down by the courts.
Now a Chinese company is buying them and there's no problems.
is that the background on that?
The Chinese company has outstanding loans, it's not an "acquisition" per-se. It's the Chinese supplier getting made whole.
Shouldn't first CFIUS oversee this takeover?
They struck it down because they said it hurts competitiveness based on faulty economic arguments. It was clear even two years ago that the market was extremely competitive with much cheaper iRobot copies. Lina Khan just didn’t want Amazon to save an American company. Plain and simple. Anybody in the robotics field in MA could have told you iRobot was struggling and that Amazon was throwing them a bone to keep those engineers afloat.