Fedex doesn't know it's powders. Fedex thinks "I have package, I ship package". Customs on the China export side is the issue. Look at your clearance detail, it'll say something like "shower caps" or "rubber gloves"...export says "hmm that's suspicious, I've approved 10,000 different shower cap shipments this month"... All this time, FedEx is still thinking "I move box from a to z"
OP