User blog comment:Omega natsu2/Episode 203: Moulin Rouge, Review./@comment-5426822-20141014210114

I know this is kinda late but I saw some people mentioning in the comments that Lucy's appearance in Erza's flashback was weird because it was before she had joined Fairy Tail; however, if you go back to the original omake Lucy is there as well. Granted she doesn't say anything and she is well hidden. http://2.p.mpcdn.net/2666/447360/10.jpg

Even if it was something the animators came up with themselves, I don't see why people find it weird, people can be in the same vicinity as one even before the properly meet one another. There's no law of nature against that :/.