Thanks for your immediate and detailed response, VincentOH. This issue with a mismatch customer assigned to an expense in QuickBooks Online (QBO) is likely due to the browser, so let's work together to troubleshoot and resolve it.

Start by pulling up your QuickBooks Online (QBO) account using a private browser (incognito). Here's how:

• Press Ctrl + Shift + N (Google Chrome)
• Ctrl + Shift + P (Firefox)
• Control + Option + P (Safari)

Once signed in, run the Profit and Loss report and reclassify the transaction using the accountant tool.

If the customer names match, return to your default browser and clear its cache. After that, log out and then log back into your account. This will refresh the system and remove older data that causes viewing and performance issues. 

However, if this matter continues, I'd recommend using other supported browsers.

Also, you can access a variety of sales and expense reports to track your business finances. For guidance on customizing, printing, emailing, or exporting any of them, please see this article: Run reports in QuickBooks Online.

In case you need further assistance fixing your data and managing expense transactions, please let me know in the Reply section below. I'll circle back to help you further.