Just had a bunch of elevation styles completely disappear from my Figma design system library. All instances are now just detached effects. I'm pretty certain that nothing was unpublished and there's no record of the styles in my version history. Has this happened to anyone else?

You can look at version history to see when (if) they were edited and restore a previous version

The effects still exist, but the styles don't. There used to be four elevations which contained drop shadows which then used color variables which were tied to modes so that I could apply a single style for an elevation and it would be lighter or darker based on the mode.