I've checked for similar reported issues on our list and didn't find any, 7674302.
We can perform a few app troubleshooting steps to isolate these kinds of issues. We can start by changing the data connection on your iPad and then close and restart the app. Then, try editing the invoice date.
If you get the same thing, you can clear the app's cache data. Here's how:
- From the Menu ☰, select Help & Feedback.
- Select Refresh Data.
- Click Refresh.
You can also try uninstalling and reinstalling the app.
Keep me posted on how this works. You take care and have a great day!