A quick update just went live with added debugging logs to help locate the bug where the same npc sometimes spawns multiple times. Most reports have mentioned multiple npc duplicates standing still in the same spot, but it appears to also happen to normal interactable npcs and monsters.
If you encounter this bug, please send a bug report in game (Options > Report a bug), as it includes important logs that might help us locate and fix the issue. Please also enable the option to send a screenshot in the bug report UI.
Thank you!