Not to be a jerk but I can't get Lacerte to produce this 'issue' at all, no matter what box(es) I check.

Exactly what entries have you made?  Anything on Line 14?  Try looking at batch entry (Ctrl W) to see if there's something random entered

Try checking the 'delete for this year' box & see what happens.   

Or you could delete the entire Screen & re-enter the info.

Or, use the 'jump to' function to see if you can track done exactly where the SE tax is coming from.

Best I can do with the info you've provided; hope one of these helps.

Otherwise, you may have to send the sanitized file to support.