Sweep produces a result that is inconsistent according to the input spine

# Path
bsplinecurve path_spline 3 11 \
3 4 \
6 1 \
9 1 \
12 1 \
15 1 \
18 1 \
21 1 \
24 1 \
27 1 \
30 1 \
31 4 \
9.00 0 0.0 1 \
9.25 0 1.0 1 \
9.11 0 3.0 1 \
8.12 0 6.0 1 \
6.52 0 8.6 1 \
8.05 0 11. 1 \
11.8 0 11. 1 \
13.4 0 8.9 1 \
11.9 0 7.0 1 \
10.7 0 4.8 1 \
10.7 0 2.3 1 \
10.7 0 0.6 1 \
10.7 0 0.0 1 \

mkedge path_edge path_spline
wire path_wire path_edge

# Profile
vertex profile_v1 0 0 0
vertex profile_v2 0 1 0
edge profile_edge profile_v1 profile_v2
wire profile_wire profile_edge

#Sweep
mksweep path_wire
addsweep profile_wire
buildsweep aSweep -C

# Visualization
vdisplay path_wire
vdisplay profile_wire
vdisplay aSweep

vfit
vsetdispmode 1