didnt get the "it's the key" achievement

[shakez]

so i wanted to get the said achievement. i did an azazel run without picking up anything but keys and item room/boss/devil deal items. from what i have read this is allowed in order to get the achievement. then i went to the dark room and killed the lamb but after that i just got the "ZIP!" achievement but no "it's the key". does anyone know why?

[kone]

Can't pickup any type of health, bombs or coins off the ground. This includes soul/black hearts and golden bombs.
Familiars that pick up any of those also invalidate the achievement (Dark Bum, Bum Friend, Bumbo)

Cards, pills, batteries, chests, keys and other resources from items given directly to you are fair game.
Most likely an unlucky circumstance you picked up something without realizing it.

[shakez]

hm i just watched a replay of my run and i dont see where i picked anything up :/ i also didnt have a familiar like that

[Ly Fecha]

I'm not sure but I heard that some of the achievments in AB+ are interverted. Maybe if you defeat the Lamb under 20 minutes you'll get the "It's the key" achievment.