This is very common situation.
It says in Finnish post site that "for example, custom clearance in the United States may delay. Due to the aforementioned reasons the shipments may de delayed for weeks".
Also, this is nothing new. For couple of years, there has been cases where cargo arrives to JFK, whole container remains unprocessed for weeks, even month(s). Then one day someone opens it and mail goes forward. Meanwhile, shipment done day before or after had no delays at all.
At the moment I have successfully sent most orders and then again, couple items bending 2 months - probably at JFK. Not scanned at USA yet.