Continuity mistake: When Linda is adding Claire's name to the calendar she added it the day before Jim died. (Tuesday). But in her flashback Claire said "I thought that after we spoke yesterday..." She said this at the burial. If the funeral is Saturday that meant that Linda went to her house on Friday. But she put it on Tuesday which is actually when she first met Claire in Jim's office. (01:00:30)
Suggested correction: All of this is correct, but I don't think it really counts as a continuity error. It makes sense that Linda would put Claire's name under the day that they first met. She does the same with Dr. Roth's name. Besides, it's still Friday morning at this point. She hasn't gone to see Claire yet. So far, she's only added to the calendar things that she's already experienced; even if she knew she was going to go see Claire that day (because of the funeral flashback), why would she break the pattern?
Trivia: Kate Nelligan plays Sandra Bullock's mother in the movie, even though in real life she's only 14 years older than Bullock.
Suggested correction: Google her age and you will see this is incorrect.
Or you could have just submitted a word change pointing out the age difference is 14 years rather than 13. Hardly makes the entry wholly incorrect.