I dont know whats going on... its just inconsistent, sometimes they appear and sometimes it doesnt (very annoying imo, i lost my entire inventory 3 times already). Yesterday i was playing with a friend, he went (first time) to the nether and suffocated in a wall (i went thru the portal totally fine), his grave just spawned on the overworld at 5000 blocks away from where we were.

What version were you on and which mods do you use

1.21 and the modpack is Better MC 3 (BMC3) Fabric

The bug is caused by Accessories mod's trinkets compatibility being broken. Technically Universal Graves works around it now too on latest version, but that modpack still didn't update to it