Hmm, I wonder what you are doing. My live home automation system shows 8 connections only.
Presumably you must have a lot of directly connected devices? Are they perhaps sometimes disconnecting and not restarting with a clean session?
Oh, I forgot, I've still got 5 other connections on my old Pi2 broker. That is bridged to my live server. Thought 8 seemed a bit low 
What version of Mosquitto do you have installed?
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