This QuickBooks behavior when preparing a new invoice can be fixed by performing some basic browser troubleshooting. Here are a few steps to narrow down the cause of this issue:
Login to your QBO account using an incognito or private browser. Since this doesn't store data in the cache, it is the best place to isolate browser issues. Kindly use either of the following shortcut keys:
Google Chrome, press CTRL + Shift + N
Mozilla Firefox: press CTRL + Shift + P
Internet Explorer: press CTRL + Shift + P
Safari: press Command + Shift + N
If it works, you may want to clear the browsing history of your regular web browser. This will remove previously stored browsing data that might have caused the issue.