Continuity mistake: Jacob Carter repeatedly mentions blending with Selmak 4 years ago, placing it in Series 4 (each season constitutes a year - when Carter leaves the SGC to join Atlantis at the conclusion of season 10, she talks to Teal'c about how they have spent 10 years together). However the blending occurred in Series 2 (6 years ago).
Other mistake: At the end, Anubis/Vaselov is sent to KS7-535 and we see a shot of the gate being partially buried in snow and Anubis frozen. However, the wormhole should have cleared all the snow in its path when it established, meaning it wouldn't be buried in the snow as seen.
Continuity mistake: When Hoskin is shot by Carter, the position of his body changes from how we see him to land to the next shot of him when Carter approaches him. At first his arm is extended and his coat lands to cover his gun. In the next shot his ark is by his side and the coat is tucked under but you don't see his gun.
Factual error: At the end of the episode General O'Neill is introduced to Joe's wife. He is introduced as General O'Neill, but his insignia on his dress blue uniform is a Colonel - an eagle, not a General's star.
Other mistake: When they are securing the base into three zones after already going into lockdown they secure zone one. Then zone three. Then zone two is secured. But because zone two is in between zones one and three it would already be secure. They are securing the zones from each other. Clearly showing O'Neill secure zone two with a closing bulkhead door displays the incompetence of one of the other two characters. (00:29:40 - 00:32:00)