google cloud platform – How do I fix a custom metric that can’t be aggregated by two projects. It says chart definition is invalid

I’m experimenting with a custom metric. The same metric and labels were being written in different projects at the same time. They should have been identical, but when I view the metric I see this:

If I filter by either project I see the metric. It looks the same so it was being written in two different projects at the same time, maybe at a slightly different interval.

I didn’t realize you could break metrics like this. Is there a way to fix this? I don’t know what the actual problem is that causes this or how to fix it.

What is happening here?