I watched the replay. The Rook has the Dark Crimson Vial. He goes back to the shop. It disappears there around 12:00. The vial icon is replaced by a grey circle. This typically happens when the item isn't written correctly or when something happens to glitch the item. At this point, until it can be replicated or more people experience it, I'm going to classify it as a random glitch.

ok so I have tested it some and have been able to replicate what happened every time. It also worked with any of the usable favor item i tried. (vial, wrath, BoS)

1. use the favor item

2. while its on cooldown purchase something at the shop (i have been just getting scaled helm)

3. while still in the shop menu right click your favor item (it may take 2 or 3 clicks but it will drop)

Yeah, just press up down up down a b a b select start. Of course, it won't work if you don't have select or start buttons on your computer. If you stab a butter knife through the screen of a GBA and then stab the sharp end (it has to be the sharp end or it won't work) through your processor, it should pick up the signal from the start and select buttons. (This may void your warranty though, so be careful!)