Error message in tfvars is not ending with a dot or question mark

TL;DR

The module is throwing an error - validation error must be at least one full English sentence starting with an upper case letter and ending with a period or question mark.

Expected behavior

Module should work without any such validation errors.

Observed behavior

The module is throwing an error - validation error must be at least one full English sentence starting with an upper case letter and ending with a period or question mark.

Below error message doesn't have . or ? at the end of sentence. File - https://github.com/terraform-google-modules/terraform-google-vm/blob/master/modules/instance_template/variables.tf

variable "maintenance_interval" { type = string description = "Specifies the frequency of planned maintenance events" default = null validation { condition = var.maintenance_interval == null || var.maintenance_interval == "PERIODIC" error_message = "var.maintenance_interval must be set to null or \"PERIODIC\"" } }

Terraform Configuration

It's failing at the time of initialization itself.

Terraform Version

0.14.11

Additional information

No response

terraform-google-modules / terraform-google-vm