Upon entering the champion select screen in draft, I found that I had access to champions I did not yet buy. I picked Trundle, and the free rotation icon was not on him. Other unowned champions were also available such as Tahm Kench. Once the game finished, I checked if I actually owned either of the two and found that I did not. There did not seem to be any prerequisite conditions for the bug to occur. Proof of occurrence is provided on the link. No refunds were used.