The environment argument is a safer way to pass values to local-exec scripts

variables_good1.tf

terraform {
  required_version = ">= 1.1.6"
}

locals {
  my_var = "12\" = 1'"
}

resource "null_resource" "good_example" {
  triggers = {
    my_var     = local.my_var
    always_run = "${timestamp()}"
  }

  provisioner "local-exec" {
    interpreter = ["Powershell", "-Command"]
    environment = {
      MyVar = local.my_var
    }
    command = <<EOC
      write-host "my_var value: $Env:MyVar"
    EOC
  }
}