Hi there, @jack78.

I appreciate you for getting back to us here in the Community. Allow me to chime in for a moment and provide some information about the issue concerning the journal entry.

To answer your question, yes, auto-voided checks for payments not cashed within 90 days are related to Bill.com. Any changes to the information like transactions being zeroed out will also sync the data into our product.

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

To contact their customer support, you can visit this link: 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.

Drop me a reply if I can help you with anything else concerning QuickBooks. Hoping you have a good one.