Welcome to the QuickBooks Community, Nora S. I appreciate you for performing some steps to fix the issue. I'll be providing details on how 13f works in QuickBooks Desktop. Then, to ensure you'll be routed to the right support team to assist you further on this matter.
Line 13f in QuickBooks Desktop is taken from amounts entered for the Other Tax Payroll Item, US - COBRA Subsidy Credit. Usually, these amounts should be entered on liability adjustments per employee as negative amounts, in order to flow to line 11e correctly.
However, the issue about Line 13f is reporting the wrong amount on 941 has been recently tagged as an ongoing issue. Our product engineers are now working to fix this as soon as possible. For now, you can fill out and file the form outside QuickBooks as a workaround.
I recommend contacting our QuickBooks Desktop Support Team, so they can add you to our notification list. This will help our engineers determine the number of affected users. You'll also receive an update through email once this has been resolved.
Additionally, I'm adding this article so you'll be able to see different details on how QuickBooks populates each Line on 941: How QuickBooks populates Form 941.
Lastly, you may refer to this article to view common issues with Form 941 or Schedule B and how to fix them: Troubleshoot Form 941 in QuickBooks Desktop Payroll.
If you have any other questions about 941, mention me in the comment section below. I'll get back to you as quickly as possible.