How do I get rid of this seam artifact?

I made an infinitely zooming polar wrapped texture(using a sample texture to test), but I get this horrible seam in it. My guess is that it’s some kind of rounding error where the texture size is being divided in half and has a *.5 decimal to it or something. Is there an easy way to combat this artifact?

Well I figured out where the problem lies. I think it’s in the mipping. When I switch the texture’s MipValueMode from none to anything else, like miplevel or derivative, it goes away. While it’s not as efficient, I’ll just have to use the derivative mode with a DDX/DDY hooked in for now.