ClassB downlink problems

Hello,brocaar teacher. In the process of doing Class B project,I encountered two problems.

  1. If end-device uses ClassB “PingSlot” RxWindows to receive the downlink data from LoRaServer,the decrypt data is not original data before encrypting.But if end-device uses ClassA&ClassC RxWindows to receive the downlink data from LoRaServe,the decrypt data is right.For end-device,ClassA&ClassB&ClassC use the the same decryption algorithm.

2.If end-device in ClassB mode initiates a uplink to LoRaServe when LoRaServer have some downlink data in queue,LoRaServer will not utilize the end-device RxWindows which Opened by the end-device’s uplink to initiate a downlink to end-device,instead of that LoRaServer will remain the downlink until the end-device uses ClassB to Open a “PingSlot” RxWindows.

I hope to get brocaar teacher’s answer,thank you very much.