Thanks for joining this thread, BeanCounter146.
I haven't received any reports about the enhancement of billable check marks on bills.
Let me clears things out for you about disabling the billable check marks on bills in QuickBooks Desktop (QBDT).
QBDT lets you incur expenses to customers when you work for them. That being said, the system will automatically check the Billable field in the Bill page when a customer is assigned to it in the purchase order. See the screenshots below for your visual reference.
You'll want to delete the customer from the purchase order (PO). This will remove the check mark when you create a bill.
I'm adding the What’s new in QuickBooks Desktop 2020 link for additional information. This includes new features and improvements in the product.
Keep me posted if there's anything else you need. I'm always around to help ensure your success.
Thank you and keep safe!