I took the drop from the fountain of youth and put in in the house, ancient herald spawned at days 60 in the house while I was standing inside, it burned everything so I got out of the house and deactivate the clock in the ruin, when I got back in the house, nothing left. I tried to get another drop from fountain of youth but the structure no longer active anymore. I had waited at fountain of youth for 5 days.
Steps to Reproduce
Standing in house
This issue has not been confirmed by a developer yet.