soonami

Yes, leaves usually do droop as the they turn colors, when the abscission layer forms, the leaf is cut off from the rest of the tree so it doesn't get anymore water and the starches and chlorophyll break down only inside the leaf while transpiration still goes on. As the water vapor leaves the leaf, the turgor pressure drops causing the cell walls in the leaf to be less rigid and droop. This may be more pronounced in your buring bush than it is in other trees, but I have noticed it with my acer rubrum

And btw, your euonymus looks great, it's almost the color of the dogwood my neighbor has. I'm sure in a few more seasons it will very, very nice. I saw some at home depot today and I almost got one to bonsai, but I ended up getting a few kurume azalea instead