This looks like symptoms of cold damage and we are receiving photos of Japanese maples like this from all over the state. Many plants were lured out of dormancy and then were hit with frosts and cold temperatures recently. On some trees we are also noticing damage on the top growth versus the bottom growth. This may be due to warmth from the ground area and and bottom growth was not affected.
These damaged portions will eventually drop out. If the tree is otherwise healthy, it will push out new growth this spring/summer. No control is necessary.

Keep your tree well watered during dry periods and make sure mulch is no thicker than several inches and away from the trunk. You can send us more photos this season, if you notice additional symptoms.

Marian