Strange slicing

I'm having a few problems slicing my object.

It is a small pulley, 20mm diameter, 4mm high.

I've set the slice height to 0.1. Infill 100%, fill pattern: concentric, top/bottom fill: concentric.

These are the results using 1.2.4 (all 1.2.x versions are the same). Output is mach3/linuxcnc gcode. The pictures are the GCode previewer (awesome feature!) and I've confirmed with another GCode viewer they are correct.

The first obvious issue is that not all fill is concentric. The first attachment is the first layer. It's fine.



The second attachment, layer 2, shows the two issues I'm having - firstly, the fill isn't a concentric fill - the first layer is, then the next 9 look rectilinear.




The other issue is the jagged perimeter - not there on layer 1, there on layer 2, not there on layer 3 (not shown). This is a round pulley (file attached)

The 3rd attachment is at 1.1mm, The first concentric fill, but the jagged inner perimeter cause a wonky fill.



There is also another problem I just noticed with this slice - layer 1.2 isn't there at all! (attachment 3)



I've attached the problematic file. It needs to be rotated to sit flat. I've also attached a lower resolution version that has been preprocessed by netfab to pre-rotate. This crashes slic3r on load.


I'm not sure if these are bugs or just operator error, so I posted here first.

Thanks for any help,
Frank