fqdn.log - Intermittent Internet DNS issue

With v17 beta1,

I am having randomly dns issue and so web surfing is not working sometimes. from FQDN.log:

SFVH_SO01_SFOS 17.0.0 Beta-1# tail -f fqdnd.log
ERROR     Sep 16 02:40:49 [4149352192]: addOrUpdateFQDNCache: FQDN Host : dropboxapi.com DNS query error; retry after retry_interval_on_error = 30  seconds...
ERROR     Sep 16 02:40:58 [4149352192]: addOrUpdateFQDNCache: FQDN Host : push.apple.com DNS query error; retry after retry_interval_on_error = 30  seconds...
ERROR     Sep 16 02:41:01 [4149352192]: addOrUpdateFQDNCache: FQDN Host : sharefileftp.com DNS query error; retry after retry_interval_on_error = 30  seconds...
ERROR     Sep 16 02:41:01 [4149352192]: addOrUpdateFQDNCache: FQDN Host : sharefile-webdav.com DNS query error; retry after retry_interval_on_error = 30  seconds...
ERROR     Sep 16 02:41:01 [4149352192]: addOrUpdateFQDNCache: FQDN Host : osdimg.com DNS query error; retry after retry_interval_on_error = 30  seconds...
ERROR     Sep 16 02:41:04 [4149352192]: addOrUpdateFQDNCache: FQDN Host : dropboxdocs.com DNS query error; retry after retry_interval_on_error = 30  seconds...
ERROR     Sep 16 02:41:04 [4149352192]: addOrUpdateFQDNCache: FQDN Host : boxlocalhost.com DNS query error; retry after retry_interval_on_error = 30  seconds...
ERROR     Sep 16 02:41:04 [4149352192]: addOrUpdateFQDNCache: FQDN Host : boxcdn.net DNS query error; retry after retry_interval_on_error = 30  seconds...
ERROR     Sep 16 02:41:04 [4149352192]: addOrUpdateFQDNCache: FQDN Host : sf-api.com DNS query error; retry after retry_interval_on_error = 30  seconds...
ERROR     Sep 16 02:41:13 [4149352192]: addOrUpdateFQDNCache: FQDN Host : content.force.com DNS query error; retry after retry_interval_on_error = 30  seconds...
ERROR     Sep 16 02:41:15 [4149352192]: addOrUpdateFQDNCache: FQDN Host : sf-api.eu DNS query error; retry after retry_interval_on_error = 30  seconds...
ipset v6.14: Element cannot be deleted from the set: it's not added
ipset v6.14: Element cannot be deleted from the set: it's not added
ipset v6.14: Element cannot be deleted from the set: it's not added
ipset v6.14: Element cannot be deleted from the set: it's not added
ipset v6.14: Element cannot be deleted from the set: it's not added
ipset v6.14: Element cannot be deleted from the set: it's not added
ipset v6.14: Element cannot be deleted from the set: it's not added
ipset v6.14: Element cannot be deleted from the set: it's not added
ipset v6.14: Element cannot be deleted from the set: it's not added
ipset v6.14: Element cannot be deleted from the set: it's not added
ipset v6.14: Element cannot be deleted from the set: it's not added
ipset v6.14: Element cannot be deleted from the set: it's not added
ipset v6.14: Element cannot be deleted from the set: it's not added
ipset v6.14: Element cannot be deleted from the set: it's not added
ipset v6.14: Element cannot be deleted from the set: it's not added
ipset v6.14: Element cannot be deleted from the set: it's not added
ipset v6.14: Element cannot be deleted from the set: it's not added
ipset v6.14: Element cannot be deleted from the set: it's not added
ipset v6.14: Element cannot be deleted from the set: it's not added
ipset v6.14: Element cannot be deleted from the set: it's not added
ipset v6.14: Element cannot be deleted from the set: it's not added
ipset v6.14: Element cannot be deleted from the set: it's not added
ipset v6.14: Element cannot be deleted from the set: it's not added
ipset v6.14: Element cannot be deleted from the set: it's not added
ipset v6.14: Element cannot be deleted from the set: it's not added
ipset v6.14: Element cannot be deleted from the set: it's not added
ipset v6.14: Element cannot be deleted from the set: it's not added
ipset v6.14: Element cannot be deleted from the set: it's not added
ipset v6.14: Element cannot be deleted from the set: it's not added
^C

Is this a normal behaviour?

Thanks