AWS VPN concurrency issues

Hey there,
I am encountering an issue while trying to create a AWS VPN. I am receiving an ConcurrentMutationLimitExceeded: Cannot initiate another change for this endpoint at this time. Please try again later. error when the network associations are being created. This is being launched in us-east-2 with 3 AZs, so it seems pretty “stock” but clearly something is going wrong. Any guidance would be greatly appreciated.

Am I misunderstanding what should be created here?
Should I be throttling the creations somehow?

resource "aws_ec2_client_vpn_network_association" "main" {
  for_each               = data.aws_subnet_ids.private.ids
  client_vpn_endpoint_id = aws_ec2_client_vpn_endpoint.main.id
  subnet_id              = each.key
  security_groups        = [aws_security_group.vpn_access.id]
}