This is not a LW error, but I want other people to be aware of it to avoid the losses we incurred.
We handle our shipping through Shipstation. We always ship on time, and Shipstation updates Amazon to "Shipped."
What we didn't know is that when we process the order in LW, it also sends a message to Amazon that it has been shipped.
When we got too busy with our brick and mortar store, employees would send out shipments on time, but, the orders might not get processed in LW for several days. Unbeknownst to us, this update to Amazon caused Amazon to classify the shipment as late.
Our seller rating plunged to "At Risk" and our FBM sales completely dried up as Amazon punished us for the "late" shipments. In typical Amazon Seller Support fashion, it was only after reopening the case about ten times that someone finally told us that the problem was Linnworks. Only after reopening the case another five times, with multiple letters and spreadsheets showing the timely shipping and confirmation dates, were we finally able to get our account taken off "At Risk" and Amazon opened the order floodgates again.
LW was not at error in this: we didn't realize it worked like that, and that we could (if I understand it correctly) disable that feature (see attached screen snip). It falls into the category of "Hey, I forgot to check that box and it cost me a $#!%load of money," which is a very broad category of Amazon mistakes. Estimated cost to us in sales $5-10,000 in a month. At least it wasn't December.
Check your shipping and confirmation settings, and make sure you process your LW orders the same day.
Good luck to all!