Integration tests CloudBuild pipeline unreliable

[aarturm]

Hi,
I'm trying to run integration tests with Cloud Build using this config file: https://github.com/terraform-google-modules/terraform-example-foundation/blob/main/build/int.cloudbuild.yaml.
Even with no modification to the Foundation code those tests are very unreliable. They fail randomly in different steps. I have to re-run those multiple time which takes hours or even days.

There are few places it fails most often, example:
Bootstrap, when assigning IAM to service accounts. SA service-<PROJECT_NUMBER>.gs-project-accounts.iam.gserviceaccount.com does not exist.
Or also in Bootstrap step error telling me CSR repositories already exist. But this steps creates new and empty projects for those repositories.

Have you noticed similar behavior as well?