If it's showing the variable, it's because you don't have the right variable. Did you click and drag it from the list?
If it is not showing the value, and is blank/null instead, two things to check:
1) Make sure the value is set before the rule runs (ie: if you have a business rule that sets the value, and a business rule that sends the notification, make sure the former rule runs before the latter, by adjusting rule order)
2) Make sure the recipient has permission to the field. So if the recipient address matches a user, make sure that user's container record has permission to the field (at least 'view'). If the recipient address does not match a user, then make sure the 'Portal Guest' role for that container has permission to the field.
I am using the correct variable, listed in the system as follows:
Service Request : [FIRST_NAME_1]
As far as the business rules, there is only one running per "step", such as assigned, resolved, or created/closed. There are no competing rules for email at the same time.
Permissions are at the Admin level at this time, with populated fields in the ticket before submission of the update.
Check your "GUEST" account's permissions to those fields. From what I remember, that guest account is used to send emails, so it needs access to the field variables.