The Russian chess champion is shot and falls to the floor, taking the chess board with him. In the next shot, when Gibson Praise is looking up for the shooter, the chess board is on the table again and with some pieces neatly standing on it. Furthermore, when we see the shooting on video during the FBI briefing, the Russian merely nudges the board with his hand, which makes it spin a few times, dislodging some of the pieces.
At 00:35, you see the Russian grandmaster capture Kh8xRg8. In the next shot, Gibson plays Rg4-g8. These scenes are in the wrong order.
The safe house where Gibson praise is being hidden is identified as being in "Centerville, Virginia." The correct spelling of the Washington D.C. suburb is C-E-N-T-R-E-V-I-L-L-E.
At 5m 20s CSM and Krycek are shouting at each other whilst standing in a snowfield.
The sound should be completely 'dead' but here it has high frequency reverb.
The Vancouver Science World (a dome like sphere) is seen in several scenes when the Smoking Man meets Krycek outside. In that particular scene, they were supposedly in the US
The mountains identified as the Laurentian mountains in Québec were the pointy Rockies of BC.
Mulder pronounces "Gaithersburg" wrong. It's pronounced with a soft t sound, but he pronounces it with a hard t.