NWK Leave commands ignored?

Hi,

I'm using ZStack 2.4.0 to build ZigBee Smart Energy devices and have used the IPD example as my baseline.  When my ESP sends a NWK Leave command: NWK Command Frame ID = 0x04 Leave with payload 0x60 (rejoin=1, request=1, remove children=0), I expected ZDO_LeaveInd( NLME_LeaveInd_t* ind ); in ZDApp.c to be called, and I can take appropriate action.  Indeed the comments say "This function allows the next higher layer of a device to be notified of a remote leave request or indication".

However, searching through the source code, this function appears never to be called.  Further, breakpoints placed in this function is never triggered, suggesting that it was never called, even as my ESP repeatedly sends the NWK Leave command.

How do I ensure that a NWK Leave command from the ESP actually triggers an event on the IPD?  Thanks.

Voon