If a user has multiple tabs open, errors similar to this may be seen. Each input form on the web UI has a hidden input field with a unique value used to validate that the committed information is correct. If there are multiple tabs on the web UI, this protection takes effect and the this error message is captured.
STATUS: There is an Enhancement Request to allow the use of multiple tabs; SYSLOGDEV-6391. Enhancement requests are reviewed periodically for potential inclusion in future releases of the product.
WORKAROUND: Do not use multiple browser tabs with the product.