- It's entirely possible, though not outright stated, that Worf started the episode in an alternate universe/timeline from the time he crossed the expanse or a bit afterwards. The ending even hints that this was the case, as the only change that seems to be from the main one was the fact that the surprise party happened in that one.
- In the last universe Worf visits, Wesley has become the Enterprise's tactical officer, whereas in the Prime universe, Wesley was about to drop out of Starfleet Academy in "Journey's End" later this season. In that episode, Wesley says that he's dropping out partly out of pressure of Picard's expectations, as he was Wesley's Parental Substitute. Riker, on the other hand, was more of a Big Brother Mentor, thus Wesley would have a closer bond with him. It's even possible that the events of "The First Duty" never happened in this timeline thanks to that approach.
Fridge / Star Trek: The Next Generation S7E10 "Parallels"