Hi,
Not sure about the scenario and context of this behavior.
In general, it may be related to network where first ACK may not safely reach to the remote end point. This is theory and I don't see (yet!) any other reason for observing repeated IPMEV_INIT_RECEIVED events. In any case, your application is doing right thing of calling ipm_InitResponseSend() for every INIT indication received from network.
Thanks,
Sunil.