Hello there, @Mophetmom.

As my colleague said, on Bill.com, check payments that are not cashed within 20 days will auto-void. Any changes to the information like transactions being zeroed out will also sync the data into our product.

Since the checks are handled depends on Bill.com, it would be best to reach out to them. One of them will be able to provide some advice about how to prevent the issue other than a manual journal entry.

You can use this link to reach out to them: https://www.bill.com/contact-us/.

For additional reference, I've attached a link you can use to learn more about entering a journal entry in QuickBooks: Create a journal entry in QuickBooks Online.

You can drop a comment below if you have other questions. I'm here to help.