There have been some timeouts when creating VMs lately. As the number of VMs is increasing so does the time it takes to create them in parallel. Recent periodics have shown it would take more than the current timeout (15min) to complete:

https://prow.ci.openshift.org/view/gs/test-platform-results/logs/periodic-ci-openshift-microshift-main-ocp-metal-nightly-arm/1788373567679762432

Raise it to 30m.