Zigeunerzelt » GYPSY CAMP?

Hi,

On the way to Britain's moongate, I found a bunch of gypsy NPCs,
with a tent, a campfire, and an inviting chest. I immediately tried to
detect hidden to see if it was trapped before trying anything else,
but after 4-5 tries, they all disappeared, bringing the metal chest
with them. What did I miss?
Please help.

I didn't find the right solution from the Internet.

References:
https://stratics.com/threads/gypsy-camp.156631/
Motion graphics service

Thanks