I'm here to help you get back to business and able to successfully change the customer's deposit, josie-ubuntutrav.
 

Have you tried performing some browser troubleshooting steps to fix this? If not yet, you can follow these steps. First, log in to your account using a private browser. There are times that the browser is full of frequently-accessed page resources, thus causing websites, like QuickBooks Online (QBO), to act weirdly. To use a private browser, here's how:

• Google Chrome: Ctrl + Shift + N
•  Microsoft Edge: press Ctrl + Shift + P
• Mozilla Firefox: Ctrl + Shift + P
• Safari: Command + Option + P

If this works, you can clear your regular browser's cache so the system can start fresh. But if you get the same results while using a private browser, use a different browser app instead.

To learn more with making bank deposits, you can read through here: How to Record Bank Deposits in QuickBooks Online.

Let me know how these troubleshooting steps help. I'll keep an eye out for your response.