GOP/ATP providing schedule arrival date earlier than request date in sales order

Hi,

We have a sales order in which the request date is 27-nov-24. on-hand is available to satisfy the sales order demand. Request date type is arrival for the sales order.

But as 27-nov-24 is a non working day in customer receiving calendar, GOP/ATP has populated the schedule arrival date as 26-nov-24 and schedule ship date is also 26-nov-24 as delivery lead time is 0. It preponed the schedule arrival date.

My question is why it preponed the date. Instead of populating schedule arrival date as next available date which is 02-dec-24, why it went to the previous date?

Any reason for this? Please help to get me clarified.