Hextech Materials Gone

Hey I was holding onto what caches I had left to see if they do another hextech event. But I logged in today and they were all gone! I lost a skin shard for Hextech Zed. Blueprints for one of the icons. About 6 or so cores. And a few other things. I'm most upset about the Zed shard. Riot, is there any reason for having done this?

EDIT I mean "PROJECT ZED" not hextech. My apologies.