When Sam and Virgil first sit down at the fire pit they each throw their beer bottle caps into the fire, and then a few seconds later, do it a second time, with the same beers.
When Michael is taking infrared pics of Fiona to determine where the laser/optical mic is, it shows that the mic is pointed at the lower right pane of the window. However, when Fi and Michael put up the vibration tool to counter the laser mic, they put it in the lower center pane. Since the window is made up of individual panes separated by wooden frames, each pane acts as it's own individual audio conduit. Therefore, by putting the counter-measure in the lower center pane it will have no effect on countering the laser mic that is pointed at the adjacent pane.
During the scene where Michael and Fiona are taking photos in his apartment, when asking how the photos turned out Gabrielle Anwar (Fiona) accidentally slips into her native English accent instead of the character's American accent.
After discovering the magnet that Michael put in the lamp (and wiped his computer), Agent Bly calls Michael. They talk and then Bly is shown hanging his phone up and throwing it on the desk right next to the magnet. This would have wiped out the phone as well.