Totally wild guess here, but your bot could be hitting the message limit? From Twitch’s irc page:
If you send more than 20 commands or messages to the server within a 30 second period, you will get locked out for 8 hours automatically. These are not lifted so please be careful when working with IRC!
Mods can type 100 messages in a channel before hitting this rate limit. If a message is sent to a room in which your global message count is already too high, you will be disconnected.