coap server: Resource callback called multiple times with multicast destination

[fgervais]

I'm experimenting with a coap server on a FTD in my network.

The server uses the higher level CONFIG_COAP_SERVER feature.

This is the behavior I get:

• If my coap client sends a request to the server's unicast address, everything is fine.
• However if the client uses the all FTD multicast address ff03::2, the server receives multiple requests.

On the network level, I think everything is fine here.
However what seems odd to me is that the server's resource callback is called multiple times even though the coap message id is the same.

Shouldn't the duplicates be dropped somewhere before the user's callback is called?