After starting Last Epoch for the first time in several weeks, in true offline mode as usual, I found that all my characters had disappeared (not just moved to legacy tab).
Note: I’m playing on Linux and previously entered offline mode via the -offline launch option. With the arrival of the launch option selector (which previously wasn’t available under Linux), having -offline specified would cause the game to silently exit during startup. Removing the -offline parameter fixes this, but previously played characters are gone.