Hello jessebarron,
Thanks for reaching out about this. I see how having the numbers not appear as you're expecting could be confusing. I want to make sure we get this taken care of so your books are neat and organized the way you'd like them.
An important detail to keep in mind with your custom form numbers is that certain sales forms, such as invoices and credit memos, use the same numbering system. I'll use your numbers as an example. Say I create an invoice with the number 18482, but then go to create a credit memo with 2020 AR. QuickBooks Desktop is going to use that format the next time you create a sales transaction, even if it's an invoice rather than a credit memo. This would mean I'd see 2021 AR instead of 18483. To use different systems for each kind of form, manually changing the number is in order.
Another thing that may be affecting this could be your custom form template. There have been occasions where a field on a custom template is incorrectly populating on the sales form itself. You can take a look at the layout designer and other customization options to make sure that everything is all right there and make changes if needed. This article can help if you're not sure where to go: Use and customize form templates
A final troubleshooting step I have for you is to check your company file for data damage. Data damage can cause weird quirks like this, but luckily we have a method for checking and repairing damage if there is any. Check out this link: Fix data damage on your QuickBooks Desktop company file
In the event you're still having trouble, contact QuickBooks Desktop support for further troubleshooting. An agent will be able to work with you to resolve this and get you back to work. This article goes over support policies, hours, and contact details: Intuit QuickBooks Desktop software support policies
Take care!
