I have stumbled upon a problem within my phase as of recent, that sometimes when I enter it, NPC's will appear as the screenshot shows.
In turn, I have found a temporal fix to this problem. The .ph rejoin seems to fix this problem, although temporarily.
The NPC appearances are made within the NPC template.
I have not tried to replicate this bug with original ingame NPC's.
Link to the Screenshot: https://imgur.com/a/waSaCmP