From v5, podman has deprecated cgroups v1 support.

"Podman will now print warnings when used on cgroups v1 systems. Support for cgroups v1 is deprecated and will be removed in a future release. The PODMAN_IGNORE_CGROUPSV1_WARNING environment variable can be set to suppress warnings."

source: https://github.com/containers/podman/releases/tag/v5.0.0

Upgrade the cluster nodes to cgroups v2 to avoid any breakage for the podman in container setup.

https://docs.openshift.com/container-platform/4.14/nodes/clusters/nodes-cluster-cgroups-2.html