Sometimes, you might see in the landing page report, that the number of leads submitted on the landing page and number of submissions may be different.
This is because a landing page visitor becomes a lead after submission. But if the same visitor submits again, it is counted as a submission and not another lead. For instance, 1 visitor submits on a landing page. The number of leads is 1. But if the visitor submits 4 times, then the number of submissions is 4.
In the below screen shot, a particular lead has submitted on a landing page twice. Although a lead is 1, submission will be counted as 2.