Problem and Solution

Solution: check top layer containing those sublayer, under layer panel, choose Release to Layer (sequence), so each take its own layer

(sequence) meas like image sequence, each sublayer as a frame of sequence

(build) means like image build sequence, each sublayer as a part of growing objects, so first new main layer is 1 obj, 2nd has 2 objects, and so on, the last one has all objects.