I’m using Unity 5.3.4f1 and my cubemap’s have noticeable seams on iOS, but not in the editor.
My cubemap settings are: Lat-Long layout, bilinear filter mode, 2048 compressed.
In previous versions of Unity, these seams did not show up on iOS.
…just throwing in a bone on the go here so I might be completely confused and wrong…but the solution to those seams might be to set the “wrap mode” on the texture to “clamp”
Yeah I tried that by setting the texture import to Advanced with clamp instead of Cubemap, but they are still there.
It looks like it might be an issue that showed up since 5.3.3:
http://forum.unity3d.com/threads/unity-5-3-gi-problems.373537/#post-2558675