Translucency Weight not up-date correctly (uber iray)

kitakoredaz

1. Load sphere primitive, then set uber iray shader >Base Mixing = PBR metalicity/roughness metalicity set zero.

only set one photometric spot light, in the scene, then render image.

2. set Base color as you like,,

3 set Translucency Weight value to 0.5, then set trasculcency color and tint color , with "Base color effect = scatter, transmit" mode.

4, turn down Translucency weight to "0.0" , now only base color need to circulate for render,. but it not work correctly.

after that, how change Translucency weight ,  all rendered color not much actuall setting.

5 to see correct color, (rendered), change Share Grossy input "ON" then return to "OFF" (though I can not follow, after that  if change translucency weight

DS show correct color or not ) or  change Grossy input "OFF" tnen return to "ON" it change rendered image color, case by case. really un-stable.