If conversations aren't defined in top to bottom fashion ( method containing startConversation is below its "next" method), they get called when a new message comes in that doesn't match any defined patterns.
(To see this in action, in the example, just move setupMeeting to the bottom of that file, and send a message that doesn't match the onReceiveMessage's pattern )

The issue starts with the constructor of BaseBot.
this.getClass().getMethods() will return the methods in no particular order. Normally, they will be in their line number order, but not necessarily.
When the methods are "out of order", this line if ( !conversationMethodNames.contains( method.getName() ) ) adds a next method to the eventToMethodsMap in error, as that method's previous might not have been added.