Pledge does not become Completed after last payment adjusted downwards

While entering the last scheduled payment of a pledge:
Click "Adjust Payment Amount"
Enter a reduced payment amount
Select the radio button "Adjust Total Pledge Amount"
Hit Save

Result: the pledge status is "In Progress" although the balance is 0. A new scheduled payment is added with status "Pending"

Expected: Pledge status becomes "Completed" with no additional scheduled payments.

A patch is attached for PledgePayment.php v4.2.6.