When DNS over HTTPS is not enabled in Firefox and I set network.dnsCacheExpiration to 600 seconds, evidence from about:networking#dns shows that the minimum DNS cache expiration time is indeed 600 seconds. However, when I enable DNS over HTTPS and set network.dnsCacheExpiration to 600 seconds, the network.dnsCacheExpiration setting seems to be ignored. New DNS cache entries are able to have far less than 600 seconds to expiry. Why is network.dnsCacheExpiration ignored when DNS over HTTPS is enabled? Could this be a bug in Firefox?