onPurchaseResponse not invoked

We've added the receiver to the Manifest, loaded the SDK tester, added a json file, and used the sample code for entitlements almost verbatim. The callbacks are being invoked, with the exception of onPurchaseResponse. The purchase UI shows up, and after purchase, no onPurchaseResponse. When clicking the 'X' to close the Purchase UI after purchase, we get a onPurchaseUpdatesResponse with the receipts, but again.... no onPurchaseResponse. Is this the correct behavior? Should we be getting an onPurchaseResponse? If so, when?

question