Digital Light & Color

Sometimes, however very rarely, it happens when I am adding and removing control points (of gray shades) that the embossed bar below the color bar gets clipped and the output image gets tinted, usually in green. The tinting is not stable and moving or clicking a control point can change the color, sometimes even back to B+W, see the attachment.
In this example when I clicked OK, the output turned red - the rightmost red patch. I have never caught the exact step when it happens as I have never managed to simulate it.
There is no way to correct it, the transformation has to be recreated.

I have not been able to reproduce this.

I have never been able to reproduce either.
I posted it just for case someone else encountered it and might brings some details.