What about if you change the texture samplers to “clamp” rather than “wrap”? - that’s not really fixing it, but at least it would show that it’s a problem with the UV going over 1 (or under 0)
Yes I can’t see any deformation on the original textures. Either on Photoshop or inside UE Texture Viewer I’ve been zooming in like crazy but they appear fine to me.
What I did find is if I change MipValueMode from None to MipLevel the seam disappear, but this is not what I want - maybe something to do with how the mips are being computed?
Right - it sounds like the mip resize filtering is averaging the left/right sides on the edge pixels… You could also test by changing the “Mip Gen Settings” in the Texture Editor details to “unfiltered” - if that also removes it then it looks like that is what it is.
Try setting “Filter” to “Nearest” in both textures - If I use BiLinear or TriLinear, I get the seam - if I use Nearest, it works - I still think it’s interpolating the sides of the textures…