Here it is.
The planes refraction apparently jumps over into the sphere, which is shown 
floating halfway in the watery looking plane surface.
The sphere itself is simply an invisible rgbf 1 pigment, a modest finish 
without any reflection and with no refraction enabled in it.
The plane does have an ior; and an inverse keyword, which I tried before and 
after the interior statement with the same result.

// Refraction bug?
// refraction seems to jump into an external object
// which itself does not have an ior
// 98.91, bob hughes

// when 1 (inverse used) refraction jumps into sphere, 2 does not
#declare RB = 1  //use 1 or 2

light_source { 0*x color rgb 1 }
camera {location <0,5,-9> look_at <0,3,0>}

// strange sphere (no refraction used)
sphere {<0,0,0>,3
  hollow on
 pigment {rgbf<1,1,1,1>} normal {wrinkles .1}
  finish {ambient 0 diffuse 0 reflection 0 reflection_exponent 0}
 translate 3*y
}

// strange plane (refraction can jump into sphere)
plane {y,3
 hollow on
 texture {pigment {rgbf <1,1,1,.5>}
  normal {wrinkles .5 turbulence .5 ramp_wave}
   finish {phong 1 phong_size 100
//please note that reflection is turned off completely
   reflection 0 reflection_exponent 1
   }
  }
 
 interior {ior 1.23}

#switch (RB)
 #case (1)
   inverse  // the culprit? or is it simply a refraction bug alone
 #break
 #case (2)
   //no inverse used
 #end
}

// base plane
plane {y,0 hollow on
 texture {pigment {rgb<0,1,0>}
  finish {ambient .15 diffuse .85 phong .3 phong_size 123}}
}

sky_sphere	// evening
{
  pigment
  {
    gradient y
color_map { [0.0 color rgb<0.9,0.5,0.475>] [1.0 color rgb<0.2,0.45,0.65>] }
  }
}
//END

-- 
 omniVERSE: beyond the universe
  http://members.aol.com/inversez/POVring.html
=Bob

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