actual texture is unimportant (you could overwrite sprite sheet with a solid white texture), just UPaperSprite .uassets that are misbehaving are what are needed for a repro (e.g., it would be fine to send just sprite .uassets that are bad, and tell us path where those assets sit as well as path and pixel size of where referenced texture should be; I can then just import a solid color texture at that location).
Note: If collision or render geometry is set to shrinkwrapped then obviously contents of texture does matter after all (but only alpha channel).