Do you know what debouncing is and how it relates to buttons ?
How long/messy is the wiring between I2C master and LED board.Leo..
I don't see any schematic so I don't know what a 'button' has to do with this post.Post a schematic that shows the button and then we can discuss debouncing.The fact that you are not clear about debouncing and why it is necessary is a red flagthat may indicate it is relevant to your issue. Without seeing the schematic of the button circuit I can neither confirm or deny that it is.
If it turns out to be a pullup resistor issue then you'll have to replace all the pullups with a higher value (15k to 20k).
Or as I pointed out, simply remove three out of every four pullups.
But I did not disconnected the boards from the circuit. I just modified the Arduino code to ignore them......make senses?