Wrong shading display of tubular arc

Hello, I have a problem for the display of a tubular arc since 7.5.0. This problem was not present in 7.3.0 , I do not know for 7.4.0 as I moved directly from 7.3.0 to 7.5.0.

I tried to change the deviation coefficient without success. I use 0.0005 for this kind of shapes and default value for others.

Anyway here is the draw script to reproduce it:

pload ALL
vinit
vsetdispmode 1
circle c0 0 0 0 0 0 1 30
circle c1 0 0 0 0 0 1 30
rotate c1 2000 0 0 0 1 0 15
circle c2 0 0 0 0 0 1 30
rotate c2 2000 0 0 0 1 0 30
circle c3 0 0 0 0 0 1 30
rotate c3 2000 0 0 0 1 0 45
circle c4 0 0 0 0 0 1 30
rotate c4 2000 0 0 0 1 0 60
mkedge e0 c0
mkedge e1 c1
mkedge e2 c2
mkedge e3 c3
mkedge e4 c4
wire w0 e0
wire w1 e1
wire w2 e2
wire w3 e3
wire w4 e4
thrusections ts issolid w0 w1 w2 w3 w4 
vdisplay ts
vfit

Best regards.

Jerome.