There are a couple of threads relating to a similar issues, perhaps related to this (using dsl rules in OH3 UI) ?
- OH3 Thing.json suddenly empty - #3 by DaDen
- Dispatching event to subscriber 'org.openhab.core.internal.items.ItemUpdater...takes more than 5000ms. And Thing are deleted
I suffered from it at the weekend, thankfully I’ve been taking regular backups so was able to restore only losing a few hours work (I’m now taking multiple backups when I’m making changes).
Cheers
James