Here ya go, fam!
https://boards.na.leagueoflegends.com/en/c/player-behavior-moderation/fnazkYWL-stereotypical-i-know-but-i-wasnt-directly-flaming-any-summoner-so-why-the-chat-restriction?comment=000200000000
[{quoted}](name=Riot Tantram,realm=NA,application-id=ZGEFLEUQ,discussion-id=fnazkYWL,comment-id=000200000000,timestamp=2017-08-01T21:44:45.446+0000)
Nope. It can be caused by as few as 1 game. Even if it was caused by a single game and the system sees other logs in your recent history that are relevant to your penalty, it will show them to you.
But honestly, cherry picking the least severe log and presenting it as though you have no idea how you were penalized, is a little disingenuous. I'm assuming you knew the first 2 were unacceptable, which is why you excluded them.
It's only a chat restriction. Take it as a learning experience, which it is intended as, because your next penalty will likely be escalated if you continue.
If our Super Smash Brothers fan is being honest, then he probably said this immediately following his previous penalty.