We have recently been running into this issue as well. Orders in On Hold status in Shopify still flow into Shipstation immediately and can be shipped. It would be great if there was some sort of stop/hold to these orders flowing into Shipstation or just more guidance on what to do with these orders as we are definitely not the only ones running into this. We have already seen where some orders were shipped with items that had not been paid for and during the hustle and bustle of the holidays, if we are not super cautious, this could continue to happen. Please look for a solution or better help for your users Shipstation!