I have just taken delivery of 12 new Colour Source Spot units. I am experiencing a strange dmx issue on power up or down. When the units are powered down and then up again, the dmx address on random units is changing, but only by a figure of one. For example a unit addressed to 55 will slip to 54 or increase to 56 and therefore not be controllable. Has anyone else experienced this? They are being used in a brand new build, so I can't rule out power issues or problems with the building dmx infrastructure, however, does anyone have an explanation for what could be causing this.