It may have happened that sometimes your orders haven't been updated on the marketplace, the solution might actually be really simple.
In case you have multiple Locations, verify from Marketplace > Edit that the Location linked to the orders not updated is selected.
In fact, you need to select the exact location of the orders for them to be updated on the marketplace.
📌 Why do I keep seeing the hourglass over Shopify icon even if I’ve just updated the order?
In this case you can try to update the orders again from Shipping Labels section clicking on Action > Update Marketplaces with shipments info
📌 What's the Order ID amount limit to be updated per minute?
You can update up to 50 Order ID per minute.