A user has sent a draft for review, but for some reason, that draft cannot be
opened, edited, published blah blah blah. Even if I delete the page from the
server and re-upload it, or send a new connection key, or CTRL+SHIFT Refresh
the drafts console or delete .LCK files from the server.

Has anyone else had this problem and found a way around it?

I'm using 3.1