Creating Group deleted all grades

Hi,

Working on a short trailer, after white-balancing all clips we did our creative grade on one clip and were going to copy it to the rest. Long story short, on our template clip, selected "Add into a new group" and all our grades, corrections and nodes disappeared from ALL clips. Removing the group created did not bring them back. Nor did simply using 'undo'.
As far as I can tell from learning more about groups, our grades shouldn't have been removed in the first place.
Is there a way to get our progress back? (Not autosave - already went down that road and shamefully it had been turned off)...

This has never happened to me. Are you sure you went through all four Node windows: Pre-Clip, Clip, Post-Clip, and Timeline? Could it be you're looking at the Timeline menu and seeing no node there?

Look at the Clip timeline display and see if all the clips you graded have a colored box around the clip number in the upper lift. If that's there, the correction should be there.

Whenever I'm doing a drastic change, I'll sometimes duplicate the timeline and perform the operation on the dupe. That way, if disaster strikes, I can always go back to the original unaltered timeline. But something like this should not happen. It's actually pretty hard to wipe out all the nodes in every clip in a timeline.