I’m using full UI based items (JSONDB), after upgrading from 3.2 to 3.3 I’m missing some location group items. When I look in my org.openhab.core.items.Item.json the items are still there. This is an example of a item which is missing from the UI.
It has never been allowed to start an Item with a number. It causes all sorts of subtle and hard to understand problems. This has been in the docs forever. But it was only in OH 3.3. that that restriction was enforced in the code.
What you’ll need to do is use the REST API to delete this and all other Items that start with a number and then recreate them through MainUI using names that do not start with a number.