Engineering Accuracy - especially in the Z direction

[Alzibiff 8]

After over a decade of 3D printing with my home built RepRap machine and using Skeinforge as my go-to slicer which I always considered to produce accurate results when it came to dimensions, I have been using  an Ultimaker S5 and slicing with CURA for the last 9 months or so - all good.

 

However, today I downloaded an STL file from the internet which was a very fine 0.2mm in the Z direction, (a Christmas decoration). When slicing with CURA V5.5.5.0 and setting the profile to one of the 0.1mm layer height varieties, I end up with just ONE layer rather than the expected 2. I have repeated the slicing operation with other 0.1mm layer height - and less - profiles with the same result - a single layer.

 

Any suggestions on what I am doing wrong or is there an explanation of why I am only getting one layer with a file which logic suggests should produce 2?  I attach one of the files that I am trying to slice which in a CAD system is definitely 0.2mm in the Z direction.

1a.stl

[obewan 37]

Make sure the initial layer height is also set to 0.1 or lower

[Alzibiff 8]

Aha! That's the setting - thank you.