Thin lines on transparent trail image

I’ve made a white gradient image that goes from fully white to fully black which i then apply to a trail with LightEmission set to 1, but for some reason there is a white line on the invisible end of the trail even though it’s not in the image:
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I tried swapping the attachments, changing the image to not go from white to black but to go from white to fully transparent and I also tried changing the resolution of the image but to no avail. Is there any way I can fix this?
Thanks in advance.