As a catch-all drop counter specific to the login-authentication path, a rise here without a matching rise in any of the more specific counters on this same table, such as malformed, bad authenticator, or unknown type, suggests an uncommon, possibly device-internal issue affecting administrative logins specifically. It's worth escalating with the full set of per-server counters from this table for context. For example, reporting this counter alongside the other login-table counters, all flat, to vendor support would help them diagnose an otherwise unexplained drop pattern affecting only administrative login attempts.