Apparently, LibreOffice does not always use the original lock token supplied by the WebDAV server, but instead changes encoded characters to upper case, e.g. uses %2F when the token supplied by the server contains %2f. This is not allowed by the WebDAV specification, which says "Clients must not attempt to interpret lock tokens in any way", see https://greenbytes.de/tech/webdav/rfc4918.html#lock-tokens. Actually this does not work at least with the Jackrabbit / Jackrabbit Oak WebDAV server, see https://issues.apache.org/jira/browse/OAK-10166.