After years of relatively trouble-free sending to Europe I've started having issues with items being returned this year, when all the parcels had the proper customs requirements fulfilled.

The only thing I can think of is that AP started requiring the tariff code to be completed for every international  destination for parcels since last year, which I do complete, and they are now also auto-signed with "ID verified" tags rather than me signing them manually.

Maybe there are some teething issues going on in regards to these things.