Skin is "Alex" in single player, but my own in multiplayer

In single player, my skin appears as Alex, while in multiplayer, it appears as my own skin. I have tried multiple single player worlds, as the one I was on was an old world, but the same issue occurred. I went on a multiplayer world to see if that would change anything, and my skin was back to my own. I restarted the game and launcher multiple times, that didn't fix anything. I re-uploaded my skin to the game, and that also didn't fix anything. It started happening today (8/19/2020).

While writing this I discovered the "Skins" tab on the launcher. I had to click my skin and tell the launcher to apply it, as it didn't apply automatically. Nobody else has used their account on my PC in a while.