Quote - > Quote - ok I see where your going.. sorry you've gone a bit wrong :( 8 is only mapping 1 side of the cylinder. the tops, sides and back are not being mapped at all and being compressed into the edges of the mapping you've got...  applying a texture to it would only work on that one side.

No.

That's not how it works.

First of all, where are the "tops", "sides" and "back" of a cylinder in a flat projection map?  That's determined by the axis and, even then, it's not appropriate to apply "top", "sides" etc.. terms to a UVMap in any meaningful way.

Notice, there are 10 faces of the vertical side of the cylinder depicted in map #8 projected along the x-axis.  The cylinder has 20 facets around its circumference.  The other 10 faces are stacked directly below these.  The remaining 40 facets of the "top" and "bottom" are incorporated into long, stretched out UV lines stacked on top of each other which join everything into a cohesive whole map.  They are hidden below the UVs as well.  There are no "missing" facets that are not being mapped.  They're simply not being mapped very well if you were going to apply a texture to them.  But, they ARE all mapped.

Is it suitable for using for a texture that wraps around the side wall of the cylinder in one cohesive band and has separate details for the top and bottom?  Not as it is presented, no.  But, that's not the issue at the moment.

whats the point in fixing the artifact if leaves you with a mesh you can't put a map onto?