I re-rolled, kingpin twitch, slayer pantheon and T1 azir, it gave me vandal bard - i don't have bard, it didn't unlock him for me and just added the skin to loot to be re-rolled or pay essence to disenchant, when it says re-roll to unlock permanent skin
This is normal as far as I am aware, it does not select a skin from your unlocked champions but from all the champions in the game.
The gold border around it means as soon as you get bard you can permanently add that skin to your account. Edit: If you ever want to unlock bard.
This is how it is supposed to work. I once rerolled three skin shards and got a permanent Phoenix Quinn. I had never played Quinn before, nor did I own her.
I ended up buying Quinn because the skin looked pretty cool. No regrets.
This is normal behaviour for the re-roll system. You can even get skin shards for skins you already own.
As others have said, this is how the system works, and in your instance, working as intended. :)
