Check if there are any .lock files in your page folders and remove them. When a user edits a page, a .lock file is created in the content folder for that page.
@theopaolo on a side note about .lock files, make sure to exclude them from Git / rSync rules or anything similar, I’ve accidentally transfered a lock file from local to live once or twice, and got similar issues as you describe until i deleted it.
I dont believe so but you could use that new Terminal plugin to do it from the panel if you really have to. I think the Janitor plugin could probably do it too.
It shouldn’t be necessary to do that, as I said above, they should be handled automatically by Kirby. Although if something like this happens, checking and cleaning up from the Panel would be nice.
Since the Terminal plugin actually displays stuff in the Panel, that would be my choice.