Agreed. It is difficult to tell. But if the bug is preventing you from processing (because you can't save the existing results) then it's essentially down time for new processing. There are also connectivity issues by region and DNS issues. It is difficult to get exact downtime considering partial failures.

That said, this is the second major asia-east1 downtime in 90 days:

https://status.cloud.google.com/incident/compute/16002