Haven't heard this being talked about, but it momentarily took me out of the movie

That email and follow-up scene!

For one, the message that was sent to her sister was so tonally different to Cee's personality, and how she would normally speak to her.

Two, it is incredibly easy to spoof email and people, and also hack into accounts that I really don't understand how her sister couldn't consider that possibility.

Then the followup scene where Cee looks in her sent items and finds the email, and then instead of again, trying to followup with her sister to get her to understand, or even maybe just reminding her that she has had an incredibly rough month and was off meds or whatever, but nope! Reading the sent email just made her feel so defeated like there was absolutely no way to talk to a close family member about it and was just like, "Well that seals it! This email obviously came from my account. No way to talk myself out of this one.. I'll just go crawl into a fetal position now..."

And finally, the way that scene was filmed, with her actions, like it was the most devastating thing that had happened to her, yet, and it just contrasted with how I felt about that particular incident, made it seem extra bad and eye-roll-worthy.

Overall a pretty decent horror film!