Other mistake: When O'Neill first goes to visit Teal'c in his cell the symbol of Apophis on Teal'c's head is upside down.
There But For the Grace of God - S1-E20
Continuity mistake: When Daniel returns to the SGU in the alternate reality and Cathrine shows him the map of where the Goa'uld attacks on Earth are, we can see that there are no attacks in the north of Europe, but when we see a closeup Oslo, Stockholm and Helsinki have suddenly been added. (00:14:10)
Continuity mistake: When they are about to blow up the ancient device at the ruins, Col. O'Neill sticks a wad of C4 to the wall in the corner, when the shot changes, the explosives have moved approximately 6 inches to the left.
Continuity mistake: In an early scene "Ma'chello" is lying in the infirmary with a oxygen mask on, it cuts to Frasier and O'Neill talking about him, then cuts back and "Ma'chello" now has nose tubes.
Continuity mistake: When the sarcophagus explodes, the blast door they escape through has no card reader. Once they stand up it's there. (00:37:55)
Chosen answer: It's never actually mentioned on the show, though in the 'Continuum' universe, she says she's been with Ba'al for 50 years.
MoonFaery