Can I still earn a Hextech chest on a champion if I had an S on them before I owned them?

I was playing Caitlyn in ARURF and I got an S, however I didn't get a Hextech chest! I'm still legible for three more. I played her earlier today when I didn't unlock her, and I don't remember what grade I got(it may have been an S, i can't remember) and afterwards I unlocked her. I played her again and got an S, no chest. If I got an S on the champ prior to owning them, am I not able to earn a chest on that champion? I've gotten chests in ARURF before, so why can't I get one now?(the others were Alkali, Miss Fortune). If anyone has an answer, I'd love to hear. [sg-soraka] UPDATE: It says now i acquired the chest. I checked loot, nothing. What gives? UPDATE 2: Okay, the chest is there now, 20 hours later after an update. Did it help? I don't know. Still didn't get an answer to the question, but yay chest!