Thanks for joining in this thread, @Steveste.

Once you open the Add Time/Cost icon in your invoice and check the Hide boxes for the billable expenses in the Expenses tab, this will automatically unbilled your expenses that were marked as billed. 

However, if these steps don't work on your end, there may be a data issue within your company file that might cause this behavior. No worries, I'll be providing you some run some troubleshooting steps that can help you get back to your task.

First, update your QuickBooks Desktop to its latest release. Doing this will resolve some minor issues in the program. Here's how:

1. Click the Help menu and select Update QuickBooks Desktop.
2. Go to the Update Now tab select Get Updates to start the download.
3. When the download finishes, restart QuickBooks.
4. Accept the option to install the new release when prompted.

Once done, follow the recommended steps provided in the conversation above to remove your unbilled expenses. 

However, if you're still getting the same issue, I recommend running the Verify and Rebuild Data tools. The Verify Data self-identifies the most commonly known data issues within a company file, while Rebuild Data self-resolves most data integrity issues that the Verify Data finds.

Please know you can always come to the Community for all your QuickBooks needs. Wishing you all the best. Stay well.