I see this in the NodeBB log file. Do I need to adjust some setting?
warn: Flooding detected! Calls : 21, Duration : 636 14/1 18:38  - warn: [socket.io] Too many emits! Disconnecting uid : 1. Message : topics.markAsRead
another one. I only have 16 categories in the forum
warn: Flooding detected! Calls : 21, Duration : 700 14/1 19:04  - warn: [socket.io] Too many emits! Disconnecting uid : 1. Message : categories.loadMore
Is your socket.io connection on xhr by any chance?
That message is from the system that prevents too many emits, it means the client side made more than 20 socket.emit() calls in less than 1 second. There might be a bug on the client side that is making too many emits.