I have taken a good look at it, and indeed, the geometry is intact.
The reason why it seems to be jagged is that the cylinder’s edges get simplified with an adaptive tolerance. I spoke with the kernel team who confirmed to me, that the boundary box (Imagine a box around the body) is really large, compared to the diameter of the cylinder.
When the boundary box is smaller, the relative diameter is higher, which makes it more circular. Keep in mind, that the edge of the cylinder is still a circle, as I have selected it, and it shows its diameter on the bottom of the screen.
To double-check, I have projected the edge to a temporary construction plane above it. I have attached an image, showing the selected edge, as well as the projected edge, proving the cylindrical nature.
