Why is Suggested Dock Date is greater than Suggested Due Date on Purchase Orders in ASCP 12.2.10?

We are using ASCP version 12.2.10. We use an Unconstrained plan. ASCP is calculating a Suggested Dock Date that is greater than the Suggested Due Date on Purchase Orders. The examples all have a Need By Date/Old Due Date that is in the past. The plan run date is March 30th, Suggested Due Date is March 30th, Suggested Dock Date is April 5th. The Organization's Manufacturing Calendar has a holiday on Friday April 2nd, but March 30th, 31st and April 1st are all open on the calendar.