The texture on beams doesn’t seem to scroll straight when Width0 and Width1 aren’t the same, causing extreme distortion unless the segment count is too high to notice.
That explains what’s going on in the gif, but there’s still the picture. They’re all in-sync but the one on the left with just 1 segment looks a lot different.
Bilinear interpolation will cost much more performance. So we are using a projective method to calculate the uv value. It will have some distortion when width difference is high. Here is an article about it Quadrilateral Interpolation, Part 1 – Nathan Reed’s coding blog