In the first season episode Cold Lazarus (1997), Carter gives a different story about her brother. Then she said that she missed him and his children and didn't get to see them enough, but now she says he has cut her out of his life and she hasn't even met his kids.
When Captain Carter and her father are in the elevator talking about her brother, the elevator numbers only move when Carter is talking. When Selmak is talking, they do not move any floors.
Daniel Jackson says, "Setesh was represented by an animal that was either fictitious or now extinct. ... anthropologists haven't discovered any fossils that point to a species like this ever existing." Anthropologists only study humans. This might include fossils of humans but not animal remains. Paleontologists would study animal fossils.
When Seth's followers are loading their weapons, several laser lights can be seen on some of the people. These are sighting lasers used on film cameras to aid in auto-focus settings.
When Daniel is explaining about Seth, he says, Seth arose in England in the early 1800s, but on the computer screen it says 18th Century, which is the 1700s, even shows on the computer screen "circa 1722".
The secret entrance cover the team removes is labeled 'CITY WASTE DEPARTMENT POISON HAZARD', but there is no lock to prevent anyone from opening it.