[2.74] Make face is creating double faces?

I’m doing what seems like the obligatory cup tutorial by Tutor4u on Youtube, and I’ve ran into a snag that’s driving me bonkers. During the steps to use F to create a face between the edges of the cup and handle, all of the faces were created fine, except one. For some reason, these 2 edges are insisting on creating double faces. I’ve hit ‘A’ multiple times just to ensure these are the only 2 edges being selected, and they are. The tutorial uses 2.64, and I’m running 2.74.

I suppose I could just select 3 edges on this one instead of 2 like in the video, but if there’s a chance on finding out what exactly is causing it so I can avoid it/be able to fix similar things in the future, I’d rather go that route.

Any help is appreciated. Thanks.

Tutorial: https://www.youtube.com/watch?v=y__uzGKmxt8

Attached my blend file just in case.


cup_faceIssue.blend (491 KB)

Thank you for that. Selecting all of the faces helped. Even took it a step further and turned it into more of a sugar bowl with the mirror modifier.