LRWAN: duplicate frames

Stack versions: LRWAN_V1.3.0, LRWAN_V1.2.3, LRWAN_V1.2.2

Hardware: B-L072Z Murata module

We are registering duplicate frames sent by the End Nodes. Doesn't happen frequent: 1% of all frames, may be less.

It happens on over all of our LoRa gateways so it doesn’t appear to be related to a specific brand of gateway hardware.