Been there , done that..
in my case, ( early on, when I rushed into things ) I had the ground return for all the LED driver chips daisy chained, so that there was a voltage drop when I connected ( in my case ) more than 3 displays. This voltage drop confused the data levels to the chips and gave odd results.
Just running a separate wire linking all the ground pins of all the driver chips solved it.
Hope it helps you....