I did print the invoice but the account summary showing the outstanding balance is not included even though the account summary feature is enabled. Invoices for all other accounts with outstanding balances are printing correctly so it seems that there is something specific to this one account.
Thanks for reaching out to us in the Community. Allow me to chime in and help make sure that the outstanding balance will show on the account summary when printing invoices in QuickBooks Online (QBO).
Since you already enabled the account summary feature, let's perform some troubleshooting steps that can help us isolate this. To start off, try logging into your QBO using a different or a private browser. There are times that the browser is full of frequently accessed page resources, thus causing some errors and/or unusual responses.
To use a private browser, here's how:
On your keyboard, press Ctrl + Shift + N (Google Chrome).