aeg 80820 leak from overflow on regeneration doser

Hi I have an AEG 80820 which has been tripping the leak detection switch. The regeneration doser had some sludge in it so we thoroughly cleaned it out and the water that had accumulated in the bottom of the dishwasher. Everything was put back together but at the start of the cycle a small amout of water comes out of the overflow pipe of the regeneration doser. It is only a small amount ( about 2 table spoonsful) but as this happens every cycle the leak detection trips after a period of time. Any ideas why this small amout of water overflows at the start of the cycle???

Lauraw