BUG: buying a vamp scepter deleting other items in inventory

I was playing a ranked game as Draven and i just finished my mercurial scimitar and then went to buy another vamp scepter for my deaths dance, unknowingly as i bought it my scimitar was deleted, at first i thought it was the activation of my scimitar as i only looked after i tried to use it but i got the item again and tried it and it deleted nothing, with the remaining gold i bought another vamp scepter and it deleted my static shiv as a result and this put me completely behind as there was no refund for the item it just vanished into thin air as far as i'm concerned. i saved the game to re-watch to see what happened but i'm unsure on how i can provide you with the game-play and action of this happening. I've never had it happen before but to scared to go into a ranked game and have it happen again.