I have a character with fixed hair texture. In order to make a luminance mask, I turn the hair white and make it self illuminated and switch off the ambient light.  However, for some reason, this no longer works.  Now, when I deleat the material changes key (in this case the hair), the material continues to animate as if the key was still there.  And when I try to cut and paste the original key (key one, see attachments) it makes no difference.  It is as if the keys have been welded into the material?  Or are invisible?

In other words, I cannot deleate or undo the new key.

What is going on?

TIA.

--Bex.