When a counter reset occurs, a NaN value can be stored via the Cortex TSS plugin. On instances with dual write, the RRD files are observed to store a null value. Because of the NaN, when querying data directly from Cortex via PromQL, aggregations fail to process.

Request from customer is to not persist NaN values to Cortex. If there is an problem gathering data from a node, just don’t persist a value instead of recording that there was an invalid value.