Bumping into a toxic teammate doesn't really have a timer in League of Legends and it can happen even before the match starts. Thankfully, we will soon be able to report and mute them as soon as we spot them.
Reporting and muting players in League of Legends is an essential feature that helps us keep sanity after encountering dummies stuck in lower tiers with delusions of grandeur which causes them to blame teammates for their own failures. Riot Games gave us tools to deal with these non-desirables in the form of report and mute functions.
Just like with any other good thing, reporting and muting teammates sometimes can't come quick enough, literally. For example, people will start fighting and being negative even during champion select, possibly dooming their team to failure before the match starts as everyone gets titled.
For that reason, Riot decided to give us the ability to report and mute players during champ select and the features are currently scheduled to arrive in patch 10.14. Andrei "Riot Meddler" van Roon noted that champ select reporting and muting might arrive in 10.15 but the wording makes it seem like this will happen only in case of an unexpected delay.
On top of that, Riot will be altering the decision-making process behind banning players for disrupting behaviour. They have been apparently relying on players clearly crossing the line in a match so that they could definitively ban them for toxicity. Some seem to have grasped Riot's methods, consciously or otherwise and have been disruptive but negative just enough to not get banned.
As a result of these findings, Riot will pay more attention to cross-match behaviour in the future in hopes of catching toxic players more often. These are just some of the dev thoughts found on the latest entry but they also seem to be the highlights.