I used to have 10-year anniversary cape for years until 1.19 came out. I updated Minecraft Windows 10 Edition with the Minecraft Launcher instead of using the Microsoft Store like I usually do and when I logged on, the cape was gone. I still have the Pan Cape but not the 10-year anniversary one. I uninstalled the app and reinstalled it with the Microsoft Store, but the cape still didn't show up.

I think using the Minecraft Launcher instead of the Microsoft Store to update the game caused the problem, but I'm not too sure.