Thank you for posting a response, nicalorber.

Aside from the steps provided by my colleague Mark_R, Make sure that the date and status are also accurate.

We can also perform troubleshooting steps to check if the transaction was successfully created. 

There are times that the browser is accessing old and corrupted temporary internet data. Thus, causing it to act weirdly. in the meantime, you can try accessing your QuickBooks Self-Employed (QBSE) account using a private browser.

These are the shortcut keys for each type of browser:

• Google Chrome - Press Ctrl + Shift + N
• Firefox - Press Ctrl + Shift + N
• Microsoft Edge - Press Ctrl + Shift + N
• Safari for Mac -  Press Command + Shift + N
•  

Once you logged in to your account using a private window, go back and create the invoice to double-check if the transaction disappears. If this works, it means you can proceed to the next  step which is clearing the browser's cache.

After you get back on track, you can check this article that will guide you in manually adding transactions in QBSE.

Don't hesitate to post or click the reply button for questions and clarification about invoices. I got your back. Enjoy your weekend!