This counter reports, in seconds, how much time during the collection period the OTUC2 signal carried at least one error. Because it is measured in seconds rather than raw error counts, it gives an admin a quick sense of how much of the day the optical link was actually unhealthy. For example, a value of only a handful of errored seconds over 24 hours suggests a mostly clean 200G path, while hundreds of errored seconds would prompt escalation.