Hi there,
trying the glass shader on a geometric structure I noticed something odd again.
So I set up some test objects and did test renders.
[attach=1]
Tried it with cylinders and unconnected plates,too.Always the same.
Here is another one with single sided square sheets.
[attach=2]
And on a Kleinbottle
[attach=3]
And yes,I've checked the normals for that one.
Also tried it with larger decay distances - up to 1e+010 - no joy.