I suspect it’s just a matter of someone getting rid of some live rounds that were not used up during the exercise. Maybe some rule that they can’t be returned to the ammo storage space after having been loaded.
But I can’t blame the Poles for being jumpy, after Obama caved in to Putin on missile defense, and got nothing in return.
Kind of reminds me of flying an Air Force II type plane, low over New York after a 9-11 attack....