It's a vignette, like the last one, it's supposed to be a "bonus" chapter and the author mention it happens "a significant amount of time after" the previous chapter. What kinda threw me off at first was that unlike the previous one, it's not marked as a .5 chapter ^^;
That say, Evie sure is going for that extra cherry on top the cake, uh ? :3
Edit : also, I do agree that the timing on that one is kinda odd. We were just in the middle of a fight with Evie asking for them to have a proper talk and we just jump to a bonus leading basically to make up sex. ^^; Kinda kill the tension built up last chapter, tbh...