When a task group with `service` block(s) is validated, we validate that there
are no duplicates, but this validation doesn't have access to the task environment
because it hasn't been created yet. Services and checks with interpolation can
be flagged incorrectly as conflicting. Name conflicts in services are not
actually an error in Consul and users have reported wanting to use the same
service name for task groups differentiated by tags.
Tim Gross