Ramstein AB, Germany, location of USAFE headquarters, got an emergency alarm over the weekend of an in-progress missile attack on the base. The alarm turned out to be false.
There are a couple of ways such a false alarm might be triggered. One is that the alarm was part of an exercise and the exercise label simply dropped or missed. Another is that, as part of a Russian exercise, by happenstance in also progress, missiles were launched at exercise targets inside Russia during that exercise’s final phase, and detection systems acted on the fact and a short time later (but after the alarm had been sent) recognized the launches for what they were and canceled the alarm.