despawning furniture

what causes things to despawn? i was in the middle of building a base on a pretty steep slope yesterday. one of the corners of the foundation is inside the ground. i put a campfire on the ground that was covering the corner and today it was gone. does it count as outside because it’s touching terrain? i only had a ceiling and 2 walls up but i know that wasn’t the issue because i’ve seen abandoned bases with campfires in them. do furnaces, workbenches, or storage despawn when placed “outside?”

Did you have a foundation? that might be your problem