I use the Gameflip API, which posts them all in order (5, 10, 15…). I have just now looked at my profile, and now all the listings are randomized.
I took a look at other sellers, to see if it happened to them, and it seems that Gameflip has made the listings randomized. It’s not a major problem, more just awkward. Though it is not a plus either. Please, only change things that make it better. (While your changing everything, have a look at that feedback system and change it back!).