So, in the last scene of Avengers: Endgame, where
Captain America flashes back to his trip to the past to return the Infinity Stones to their rightful places in space-time,
he dances with
Peggy, his past [romance-partner thingy].
The two characters being respectively referred to as X and Y.
In that scene, it is clear that X and Y are dancing backwards. That is, Y's right arm is clearly visible on X's back, meaning that Y's left arm is extended outwards. Therefore, Y is the leading partner in the dance. However, traditionally, this general style of dance has the male partner lead, which is inconsistent with Y (female) leading the dance.
I can't get that (horrible quality) leaked video into the question without spoilers, but I was just using it to show what scene anyway. I've seen the movie, and I'm pretty sure that I remember which person was where, but an image would be appreciated if one exists.
What's going on here? Why are the two dancing backwards? Am I just blind? Is this a mistake? Is there a reason why this occurs?