We are occasionally seeing this error when using GCP with TechPreview, i.e. using CAPG.

waiting for api to be available
level=warning msg=FeatureSet "TechPreviewNoUpgrade" is enabled. This FeatureSet does not allow upgrades and may affect the supportability of the cluster.
level=info msg=Creating infrastructure resources...
level=error msg=failed to fetch Cluster: failed to generate asset "Cluster": failed to create cluster: failed during pre-provisioning: failed to add worker roles: failed to set project IAM policy: googleapi: Error 409: There were concurrent policy changes. Please retry the whole read-modify-write with exponential backoff. The request's ETag '\007\006\033\255\347+\335\210' did not match the current policy's ETag '\007\006\033\255\347>%\332'., aborted
Installer exit with code 4
Install attempt 3 of 3

Here is an example:
https://gcsweb-ci.apps.ci.l2s4.p1.openshiftapps.com/gcs/test-platform-results/logs/periodic-ci-openshift-hive-master-periodic-e2e-gcp-weekly/1813424715671277568/artifacts/e2e-gcp-weekly/test/artifacts/cluster-test-hive-310440d4-8bfb-40f1-a489-ec0a44a7852e-0-m2gqq-provisio29dxg-installer.log