I was just working in an assignment in InDesign CC2018 and took a minute to write an email and when I got back to the document (still open, I never closed it) it shows the assignment is now locked, checked out, and in use by … me, but I cannot edit it now, it shows the pencil with the line through it and I cannot think of how to regain access to the assignment.
Do you mean the story or the assignment? It sounds like you’re familiar with the process, but just to be clear, you don’t actually check out the assignment. You check out the stories within the assignment. I think you’re seeing the pencil with the line through it on the stories within the assignment? Is there a chance you’re running InCopy on your computer as well and you might have the file open in InCopy? Any additional info might help to determine the problem.