Why do 16-bit addressed packets of Tx data always appear at the receiving Xbee as 64 bit messages?

In the situation of having two Xbees set up as Coordinator and End-Device and associated to each other, if I send a 16-bit addressed broadcast message from End-Device to Coordinator, or vice versa, the data packet always transmits and is received OK.
However, what comes out of the receiving Xbee’s DO port does contain the correct data as sent, but the complete message is not 16-bit addressed and has been converted to a 64-bit addressed message.
Why does this happen and is there any way of sending a 16-bit message once an Association has been set up between the two Xbees?

Geoffrj,

Which XBee module and related firmware are you working with?

Digi Support