Skins Not Appearing [Gameplay]

Right after Christmas, I noticed that my skins were frequently absent from my champion. This went on for a few weeks, then it stopped. I assumed that this was a known bug that had been fixed. However, this bug has started happening again. In about half of my games, my skin totally fails to load. I am absolutely sure that I'm not forgetting to equip the skin. I even have stared at the skin selection menu, with my skin equipped, right before the game started, but in the loading screen and in the game my skin did not show up.

This bug seems random as to when it takes effect. There doesn't seem to be a pattern of which champions or which skins are bugged, but this only seems to be a problem in Team Builder.