That should be fine. There's no expectation that you "should" use the earlier voucher. But if you have an issue with redeeming any new voucher you get, you can create a ticket for the Training Team. https://help.databricks.com/s/contact-us?ReqType=tr...
Please open a ticket to the Training support team. They can advise best. https://help.databricks.com/s/contact-us?ReqType=training. But as far as I know this should not be a problem.
If you have a Support contract, this would be a good one to create a ticket for.
That being said, is there a reason you need to be on classic? Its an engine that really should be considered a good starter engine but you should be using Pro or Serverl...
