If you look at the Huawei controversy the intelligence community appears utterly convinced that these hacks are occurring. But the current trade war with China makes one wonder whether the threats are exaggerated or outright fabricated. OTOH, the negotiations also mean the U.S. has an interest in not disclosing details of actual incidents, to help China save face and also to preserve U.S. domestic markets as gambling chips--i.e. if it disclosed serious and pervasive attacks then nobody would buy Huawei, so China would have less of an interest in making concessions so sellers like Huawei can grow in the U.S. market. (Similarly, SuperMicro, Apple, and Amazon are American companies so U.S. officials have an interest in limiting the fallout to any actual attacks as long as the immediate threats are removed, which doesn't necessarily require the knowing cooperation of those companies.)

The last public statement from Bloomberg was that they were going to perform an in-house review. I'm just going to wait things out.

That said, the evidence for the viability and practicality of the alleged attacks has only grown. The alleged technique has already been demonstrated. See https://www.youtube.com/watch?v=C7H3V7tkxeA Nobody seriously doubts that China is motivated to perform such hacks, and we know that the NSA has performed similarly complex hacks (the cost+benefit calculus isn't always intuitive to outsiders). So whether it has or has not happened is really only consequential for the credibility of Bloomberg.