I found the cause of the 1 second polling. Unfortunatelly the amount of typos in the provided code is big enough to cause many headaches... I compared the #defines in my code that kept polling no matter what I did to the sensor network demo that does not poll and I found a different definition. ZCD_NV_POLLRATE was defined as 0x25 instead of 0x24. Very strange typo considering it is followed by ZCD_NV_QUEUED_POLL_RATE which was also 0x25 and should have raised a warning to whoever wrote it. Anyway, setting to 0x24 stopped my code from constantly polling for messages from the coordinator. Now I can shut down the coordinator and the end device doesn't even notice it. Good luck and let me know if this worked for you.
#define ZCD_NV_POLL_RATE 0x24 //0x25
#define ZCD_NV_POLL_RATE_LEN 2
Best regards,
Florin.