Last elder guardian (Constructor) can't be despawned after being killed

I've killed the Constructor thrice right now, i can't get it to despawn from the atlas. The events trigger as intended, the elder coming and taking his soul after he's dead, but he's still there after i exit the map.

Map location : Laboratory. I have it shaped (T13), but i'm using the regular variant for the kill (T8).
Elder is just above on Moon Temple.

Any ideas?