I'm admittedly not an Avid expert (I do most of my grading in Davinci) but I encountered a glitch last week that I can't find an explanation for.
I was grading along, and was about 34 minutes into a 42 minute show. We stopped down the machine to install some effects that hadnt been loaded yet, Avid FX and i think Boris. The installer got hung up and after awhile I did a force quit and rebooted the machine. When I looked back at my timeline, about 75% of the color correction I had done was gone. Many of the clips had lost their little green line, and had no color correction. It seemed to follow grouped clips, so if one clip in a source clip name group lost its grade, they all did. This was quite disconcerting, but luckily I was able to rebuild the sequence from attic bins. It seemed that at a certain point the sequence went haywire, and lost most of the work, and that it had happened before the effects intall problem. So that may not have been related.
Any ideas? The way I have been working is to grade in "source clip name" mode, then, when I needed to adjust one of the clips of this group, I went clip by clip in "Source segment" mode so as only to affect the individual clip and not the group. I'm working in Symphony 6, with the Avid Artist Color control surface.