Hi johnpetersen,
One of the benefits of using a cloud-based program like QuickBooks Online is that you'll see live automatic updates, such as when your invoices have been viewed by your client. I know how helpful it is to keep tabs on these sort of details. I'll explain why you may have received payment from your customer without the original invoice showing as Viewed.
In order for the invoice to show as Viewed in QBO, your customer must go through a few prompts within the email. When they open the email, they'll click Print or save. From there, an external web page will open where they can either view the Balance Due, or they can get more information by clicking View invoice and more info.
If your customer didn't click View invoice and more info, the invoice won't appear as Viewed in QBO. Perhaps they've simply sent you their payment based on the Balance Due.
Simple as that! I hope this helps clear things up for you so you know exactly what's happening. If you have any other questions or concerns about this, please reach out to our tech support team.
Have a wonderful weekend.
