Usage of the vertical line, a standard ASCII character, in node names was allowed by magnolia.utf8.enabled=true. First activation attempt of such node is successful, on the second attempt it fails with NPE (attached) that it can't resolve the source at Author (the destination at Public was resolved properly during the process of removing all existing properties). So apparently an issue of en/decoding.

The workaround is to get rid of the content in question for Public (either delete it directly or deactivate (!) from Author) and reactivate.