Desert Spring Map Boss Killed - No loot or map completion

Bug report reference number: 2,125,924,579

Using Tukohama Vanguard spectres that applied a burn on map boss Terror of the Infinite Drifts.
As the boss was just about to die, it used its move where it burrowed into the ground. Been walking around the arena for a few minutes, the boss has yet to appear from the ground. The arena is still sealed as though the boss hasn't been killed. The atlas does not show completion either.

Screenshots may not be so relevant.

Have the same issue.
I kill the boss, he drops nothing and doesn't count as completion on my atlas.
I can't progress due to this. Please fix it already.

Same thing happened to me: Boss got killed with a damage over time effect (Essence Drain) while burrowed. Then the corpse appeared and teleported around to the location of my character, as if it where still alive and burrowing and reappearing. Death related effects didn't trigger, so no loot and the sand barrier remained. After I quit POE and returned to the map, the boss was alive again with no visible HP bar and died after a single hit, which fixed the issue (loot dropped and I could return to the map).

Maybe this is related to the current bug of beasts getting stuck underground while capturing them? Maybe a Programmer assumed monsters couldn't die while underground, forgetting about DOT effects.

Just a passing question: Are you killing the boss with the same character that opened the map? If not, you won't get anything for the kill. If so, forget I passed by. I haven't actually played one of these maps yet.

Same issue. Boss is stuck underground. if i nudge him he comes up but for a second and moves but is not targetable. Logged out, restarted, no luck.