Hi office218,
A runtime error can in relation to a browser issue which is creating this unusual display message or unexpected errors.
QuickBooks Online uses browser cache and cookies to run faster. But sometimes these can also block web pages from loading normal .I would encourage you to try some browser troubleshooting steps available in the guide here, includes trying a different browser.
If the issue continues after trying the browser troubleshooting steps don't hesitate to reach out to our friendly support team by clicking here.
Thanks,
-Steven