M2GO-HD Laggy Faders

Since our upgrade to 4.6, Our M2GO-HD has developed really laggy faders when using more then 2 faders. And since we use Key Lights for our stage we usually use about 4 at once to fade 4 lights down at the same time and all the lights cut from 100 to 70, 40, 0 with no fade. Just to clarify its not a cuelist, override or anything that wont allow fade. Its just a submaster. The fade works when using 1 or 2 but more then that it becomes really laggy. Is there any type of firmware upgrade for the desk only? We are now using 4.8 and its still really bad