MQTT Input Node Sends CPU 100%

I tried to disable flow by flow util the problem stopped, I don't know what is the connection, but the problem stops when I disable the flows that have MQTT connections. When I start enabling the flows with MQTT connections I start having huge CPU spikes and delay in the browser when accessing the http node... I keep enabling the flows until the spike is so big that it goes to 100% and I get a timeout in the browser.