yitz:
The latency increase is likely due to the Indigo West cable system undergoing maintenance and additional latency incurred on re-routed paths. The Indigo West is one of three cable systems (SMW3 and ASC being the other two) between the west coast of Australia and Singapore and carries much of Internet traffic between Aus/NZ and Asia and Europe.
Example of notice from an Australian ISP: https://advisories.internode.on.net/item/20406/
That's great info. Many thanks.