Hextech Crafting (Bug or Feature)?

I had a Hextech box, opened it and received a skin shard. I used that skin shard with two others to unlock a permanent skin. Once the process finished and the skin was available to be redeemed via the "Unlock skin permanently" button I left the interface by changing tabs and did not press the button. I then went to check my collection of skins, the skin was not there and my skin shards were consumed. I have had this happen to me previously while Hextech crafting and being put into a game before I redeemed. I am wondering if this is intended or an unintended bug?

Thank you.