Thanks, I haven't used Twitch before, however I set up an account, installed mTwitch, and connected to irc.chat.twitch.tv. I joined several popular channels for several hours but the debugger did not pick up any issues during that time. I will try again later for a longer test period.
In the meantime: if you have catching enabled for URLS or Emails in Options/IRC/Catcher, please uncheck them. I am trying to narrow down potential causes and there was a big internal change in the URL/Email catcher in v7.46. Does disabling these options resolve the issue?