I'll ensure you're able to view the missing transaction in QuickBooks Online (QBO).
Your bank’s connection may be interrupted for any of the following reasons:
If there is a minor or major update in your bank information such as the bank account number.
Update your Online Banking Login credentials.
Bank outage and other scheduled maintenance.
In the meantime, let's perform a few manual updates to refresh the connection between your bank and QuickBooks Online. Here's how:
On the left navigation menu, click Transactions.
Choose Banking.
Select the respective Bank and hit Update in the upper right. QuickBooks begins updating your account.
You can do this 2 or 3 times during non-peak hours.
If you still can't find them, you can download the missing bank transaction manually from your bank's website and import them into QuickBooks. Log in to your bank website, then download CSV files of your transactions. I've included the following articles below for more insights: