No chat restrictions, Level 5 honor - 14 day ban for trolling in chat for 1 normal game???

I'm confused? Are any Rioters able to clarify if this is a bug? It was instantly after the game finished too so it was clearly an automated thing rather than a case review of some kind. I could understand a chat restriction but I was even clearly sarcastic with most of my trolling: such as telling the support to sell all their items and buy a sightstone or I'll afk (which I'd do for everything, despite playing seriously the whole game?). Just seems hugely blown out of proportion considering I am even Honour 5, have no punishments before hand, and it being a normal game.
Report as:
Offensive Spam Harassment Incorrect Board