Xera Downstate Bug
My group has been experience the same thing consistently on each Xera attempt. Our consensus is that the cause is probably the bloodstones.
We think that if you go down in the bloodstone aura you can’t be rubbed back to life ‘normally’. Perhaps this is for lore reasons (bloodstone trapping spirits and what not) or this is a bug linked directly to those.
Either way, maybe this will help with a bit more insight.