The emulator and debug environments are pretty different to production. Notice that the problem is in the DATA. I can debug locally just fine on my dozen test accounts. But when I have millions of devices and tens of thousands of active users in production it’s not something I can simulate locally.
In IaaS I can just connect to the remote DB from my local app and debug with real world data. Google doesn’t provide anything like that.
They have a python tool to download the database which doesn’t work on much smaller data than what we have. I heard of people who got it to work but all of my attempts failed. Regardless it wouldn’t have been practical to download our amounts of data to debug this.
Like I said, we were a gold customer meaning we paid Google extra every month to get proper engineering support. I’ve been to their offices for personal meetings where they promised to help… This is just not the case. They don’t have an answer on this.