Thanks for bringing your question to the Community, I have some clarification on this matter that I'm sure you'll find helpful.
QuickBooks Online automates the categorization of your transactions based on the data that your bank provides us. It's possible that there was a problem with the connection when it was downloaded and due to that, the transaction synced as an expense.
To correct this, we'll need to verify the integrity of the transaction and the following steps below will guide you with that process.
First, let's exclude the transaction:
From the left menu, Click Banking.
Go to the For Review tab.
Select the checkbox of the transactions.
From the Batch actions drop-down menu, choose Exclude Selected.
Next, we'll to update your bank account to re-download the transaction:
From the left menu, select Banking.
On the Banking page, click Update.
For additional information, I recommend following these articles:
If the amount still shows up as an expense, I recommend you get in touch with your bank. They should be able to correct the transaction for you. Once they've corrected it, go back to QuickBooks and repeat the steps I provided.
Let me know if you have additional questions or concerns. You can always add a comment below. Wishing you and your business all the best!