Encountered an issue: Opensearch upgrade got stuck during the validating phase (2.17 → 2.19)

Current Versions (relevant - OpenSearch): 2.17
Expected Upgraded Version (OpenSearch): 2.19

Describe the issue: We attempted to upgrade our OpenSearch cluster from version 2.17 to 2.19. However, the upgrade process is stuck at the validation step in the OpenSearch Console, as shown below:

Configuration:
We manage the cluster using Terraform, and the relevant portion of our configuration is as follows:

  cluster_config = {
    dedicated_master_enabled = var.opensearch_config.master_instance_enabled
    dedicated_master_count   = var.opensearch_config.master_instance_count
    dedicated_master_type    = var.opensearch_config.master_instance_type
    instance_count           = var.opensearch_config.data_instance_count
    instance_type            = var.opensearch_config.data_instance_type
    zone_awareness_enabled   = var.opensearch_config.zone_awareness_enabled
    cluster_version          = var.opensearch_config.cluster_version

    zone_awareness_config = {
      availability_zone_count = var.opensearch_config.availability_zone_count
    }
  }

The only change made was updating var.opensearch_config.cluster_version from "2.17" to "2.19", and then applying the changes through Terraform.

Has anyone encountered a similar issue where the OpenSearch upgrade process gets stuck at the validation step? Are there any known workarounds or additional steps we should take to proceed with the upgrade?