Hi, Some of the Ivy particles dont show transparency. I`ve checked normals and they`re fine.
Yes it looks like its a particle system problem as it displays some of the faces differently. Sorry for late response.
That's really strange.
Notice how the planes that have no transparency have a lighter colored outline, like they are the active selection.
Usually the Object that has the particle system has the lighter outline and the particles have the darker outline but that doesn't seem to make any sense in your image...