Hi,
Thanks for the video, it looks like it only happens when rendering with IR.
If you render with the production renderer then you will get the prompt to save the file.
I have just tested and it behaves the same in v5, however I'll see if there is something we can do about this.
In the mean time a workaround would be to just save the file before you reset it (File->Save). In this case the lightmix values are stored and correct the next time I load the scene.
Cheers,
Rowan
(Internal ID=544069227)
