Also, if you Whistle Warp to a dmap that uses a different set of colors, the colors for the dmap you came from will be used until you finish the transition, at which point the correct colors will be instituted. It looks kinda awkward and could cause some visual issues for people who use multiple dmaps in overworld design, though at least it still is functional(much unlike using a Scrolling Warp to go to a dmap with different colors which is just completely broken).
All other issues with the Whistle Warp seem to function flawlessly in b215.