Skin shop's "Release Date" sorting is not correct.

When I go into the shop and look at skins, then sort by Release Date, the top two skins aren't recent at all, while Arcade Riven and Battle Boss Blitzcrank are down near Frozen Shen and a bunch of other 520 skins. Past that there are a bunch of other old skins... Then suddenly a long streak of recent ones: Captains Gangplank and Fortune, Rogue Admiral Garen (most of the other Bilgewater skins are up near the top, except I'll get to Cutpurse TF later), Pool Party Mundo (the other recent Pool Party skins are near the top), all the Prehistoric skins, Nightmare Tryndamere and Knockout Lee Sin, 3 of the "suits" skins (Queen of Diamonds Syndra is near the top, Jack of Hearts TF is near the bottom), Star Guardian Lux, Blood Moon Zilean, the Guardians of the Sand (other than Xerath, who is near the top), Order of the Lotus Irelia, Arclight Vayne, Omega Squad Teemo, the April Fools skins (other than Urf the Nami-tee, which is near the top)... And then it seems to continue, as far as I can tell it's all in release order after that, until it gets to Magnificent Twisted Fate, after which we start getting very recent skins again, starting with Cutpurse Twisted Fate, Risen Fiddlesticks, Debonair Galio... and then it continues in release order to the end. Basically, the skins seem to be completely randomly separated into three "sets", then the three sets are ordered by release date separately and put one after the other (except the first one has Arcade Riven and Battle Boss Blitzcrank, which for some reason swapped places with Sabretusk Sejuani and Prototype Viktor).

EDIT: After further investigation, it appears that this issue doesn't exist until I change the sorting, and goes away after I move to a different area of the shop or leave it. I can also change filters without affecting it. However, once I do change the sorting and then return to Release Date it always ends up in the same order. I haven't tested whether buying a skin changes that order.