> "XXX is being investigated" implies there's some kind of possible wrongdoing here.

There clearly is some "possible wrongdoing here", hence the investigation which has been launched if for no other purpose than to rule that out.

> They're investigating a potential influence operation involving the CEO

They're not investigating what we already know. The presence of a spy leaves no doubt that Huang was the target of an influence operation, the primary concern now are the details of Huang's conduct with respect to being targeted.