CuraEngine is a powerful, fast and robust engine for processing 3D models into 3D printing instruction for Ultimaker and other GCode based 3D printers. It is part of the larger open source project called "Cura".
Fairly sure that some compensation is in place for fixing the extrusion lengths for higher radii, but it doesn't stop the layers from separating at around 20+
Especially for the longitudinal seam, the lack of overlap makes the seam quite weak. The slicer attempts to make the exterior dimensionally accurate and the seam is treated at exterior so it's technically not overlapping at all.
Layer 25 (24 in g-code) of test cylinder and layers 43 and 44 (42 and 43 in g-code) of test cube have small bad extrusions sticking out. More details to come
Layers 99+ for test cube print show some artifacting which is thought to be because there are a large amount of travels (and therefore cuts) being inserted for relatively small amounts of extrusion.
So I added the segmentation to B extrusions into the FlavorParser of Cura but if you slice from inside Cura it doesn't go through the flavor parser it just kind of shows up in Cura. Probably should have seen that one coming.
The infill is calculated assuming that the X axis is in millimeters while it is actually in deciradians. For a completely filled in layer (62.8... deciradians) it is only accurate when the surface is exactly 62.8 mm, or at a radius of 20mm. Lower than 20mm the surface will be smaller than 62.8 deciradians and the infill will be too dense, higher and the infill will not be dense enough.