texturemaptocylinder always removes seam (5.6.x)
- Create a cylinder.
- Increase it's resolution to something less blocky (20 works)
- Apply a the 'texturemaptocylinder' filter with an appropriate image. (An earth map works well).
- Uncheck 'prevent seam'.
The image will display on half the cylinder, and then repeat on the other half inverted as should only happen with seam prevention.