When you edit a node, you might get into the screen telling you about a version conflict such as unsaved draft from yourself or another editor.
If you haven't seen it, It's means you don't have one.
You can also check the versions on the left side in the 'Object information' box and click on 'Manage version' to know more about. If you still have some problem ONLY with this node, delete it and typed it in again....
