Leevers 1s and 3s can't walk on a combo that is directly below a unwalkable combo they can walk parallel allong side unwalkable combos horizontally just find though.
Sorry, they walk half way and submerge.
Leever Movement
Not sure if I understand this one, but for Leever (1) to be unable to emerge when Link is halfway on unwalkable combos is consistent with NES behavior.