If Link has the the flippers, he will flicker between his swimming and walking animations if he is standing above walkable water while he's in mid-air after using his current Roc Item.
This is yet another issue with the 'Link Drowns in Walkable Water' Rule, plus Diagonal Movement.
http://www.freewebs.com/masterpikachu/ZC%20Content/Incomplete%20Quests/LOZ%2DGeneration4.qst
EDIT: I forgot to mention that this only happens if Link has the flippers.