Change PVC access mode for Prometheus/Alertmanager

i am running an AKS cluster and i have deployed Prometheus and Alertmanager via deployment resources in k8s and they also are controlled by replicaset.The issue is that sometimes the restart of Alertmanger get stuck.It is related to accessMode of PVC.During restart,k8s will start the new pod in a different node from the currently node where the running pod is assigned,depending on resource utilization on the node.In simple words it means,same PVC is accessed from 2 different pods assigned to different nodes.This is not allowed because in the config of PVC i am using accessMode ReadWriteOnce.Looking this comment in github for prometheus operator seems to be by design that option accessMode ReadWriteMany is not allowed.

So my questions, why such design and what could happen if i change accessMode to ReadWriteMany?Any practical experience?