Perhaps the most-speculated-about Euphoria plot hole revolves around the Jacobs family portrait, which shows Cal and Marsha with three children. Two of them are obviously their two children, Nate and Aaron... but who is the third? The show has shown the portrait m times (first in the pilot episode and again when Cal takes it before leaving his family in season two), which implies it's not an error. Still, the show has basically ignored this up until this point, as it has failed to explain the third child.
Fans have been reaching desperately to connect the dots, with some TikTok theorists posing that it's Elliot or Ashtray in the photo (though, both theories are unlikely considering the youngest child in the photo would be older than Ashtray at this point, and the child doesn't look like Elliot).