In ATM10 To the Skies, the execute modifier seems to void soul bound(?) items from other players when executing them. Upon respawning, none of the soul bound gear stays equipped/in hotbar and the gravestone only contained whatever random items players had at the time.
Clip of it happening - all gear that disappeared were soul bounded
https://www.youtube.com/watch?v=jhe-rfMaFt8

Should be resolved by 7504afa