Without seeing a picture, I suspect aphids. Had a Acer shirasawanum 'Aureum' open up this year with the same type problem. The first clue was a parade of ants going up the trunk. Ants and aphids often go together. The aphids sometimes create a gooey mess in the leaves just opening up. Perhaps someone more knowledgeable can comment on whether the aphids actually lay their eggs in the PRIOR summer/fall, to hatch in the following spring. This may obviously dictate when you need to spray. Do some of the leaves look like they were munched on while in the bud?
