There is a glitch in TouchDesigner's Ramp TOP at half sub-pixel phase values where the gradient doesn't go from maximum to minimum in one pixel. This can cause glitches in instancing data and other cases as well (as shown in this video
My free RealRamp component produces a gradient jump from maximum back to minimum in one pixel/sample using GLSL. It is not a full replacement for Ramp TOP, but has the most common features of it --- glitch-free!!!Parameters are a reduced set of the Ramp TOP so I will not go into details here.