Hmmm. Hard on perennials when warm weather breaks out after a cool snap. When I leaves back East I noticed sometimes trees would have tiny buds during the winter and they sprout in the spring. I noticed a similar thing as yours on a Japanese Maple 🍁 down the street. I think the leaves just haven’t turned yet.
FYI - That is a beautiful tree! I recently planted two Japanese Maples in my yard, Acer Plamatum, Shishigashira and a Crimson Queen.
The green is brand new growth. That is why I posted it - I have not seen that since I planted that tree. The one in the front yard doesn't get as much sun - Out looks like a tree going through fall. Leaves are all brown now and with the next storm - Back to raking again