Not directly, but it might muddy/complicate the EAR rules in general and which makes shippers not only more cautious but makes it also more difficult for shippers to abide timely by the ever changing rules. Amazon has more manpower to sift through the rules jungle than perhaps any of those mail forwarders.
Could be either that ECCN | CCATS were not available in the custom’s database at the time of the order but are now or Amazon meantime got around adjusting to latest EAR rules.
Anyway, that is all speculative but at least you got an option now if the mail forwarder does not work out.