Hi there, @PT20.  I've got steps you can follow to sort this out.

But before we get started, would you mind if I ask what are these specific reports you've run? This is for me to evaluate and try it here on my end if we'll have the same result. Also, I can provide you with an appropriate solution. Any additional information will be much appreciated.

While waiting for your reply, let's perform these steps to verify if this has something to do with your browser.

Usually, unexpected behavior within the system is caused by browser-related issues. Regular browser stores cache files that make frequently accessed sites such as QuickBooks don't function well.
 

To check, let's log in to your account using a private browser and run a report from there. It ignores websites from using cookies and doesn’t record any history and data.

Here’s how to do the private browsing:

• Safari: Control + Option + P
• Google Chrome: Press Ctrl + Shift + N
• Firefox or Internet Explorer: Ctrl + Shift + P

If this works, you can clear your browser's cache to refresh it. Click this link for the guide: Clear cache and cookies to fix issues when using QuickBooks Online.

If the issue persists, I'd recommend switching to another supported browsing application.

Lastly, feel free to browse through this article that you might need in case you want to use your reports outside of QuickBooks: Export your reports to Excel from QuickBooks Online. 

I'll be putting an out eye for your reply and as always, you can ask for assistance from us with regard to running reports in QBO. Just leave a comment by clicking the Reply button below. I'm always here to help.