Ironically, I also was doing a vocal session yesterday and did not realize that Takes to Layers was off until we were 80 percent done. I know that the other clips still exist as they show up in the pool. Now I want to know how to make them "reappear" even if I manually have to move each to its own layer.
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Update. My solution was to copy events from the pool. Then under the Edit menu choose Move to Origin to get it lined up again. Painstaking, but at least everything is there.