@gpspilot:
You problem does rather sounds similar to #23164, #23314 and similar recent tickets. We suspect a plugin to be the issue. Please create a new ticket with your status report and what actions of plugins you used during the session.
You should be able to save your data layer to a file. Please attach it to the new ticket.
In order to rescue your work you can try to download the missing nodes with Download Object using "nodes" and the list of ids of the non-existing or invisible nodes. If this does not work you need to modify the saved file in a text editor and look for <way id='-63' and possible <member type='way' ref='-63'. If the latter does not exist you can safely delete the way in deleting the block of lines starting with <way id='-63' and ending with </way>.
