I'm trying to set the extended PAN IDs on some XBee3 Zigbee modules that I'm testing to separate out my network from other ones in the building. I'm having issues with setting the extended PAN IDs and keeping the setting. I set the extended PAN ID to a value for the Coordinator through XCTU. I then have another Xbee3 Zigbee module I'm using as a router that is connected to a microcontroller. I set the extended PAN ID on the router using the AT Command Frame (0x08) in API mode. I do network discovery from the Coordinator in XCTU and I see the router is part of the network. Checking the router's configuration settings through XCTU (i.e., Coordinator querying router for settings over the air) I also see the extended PAN ID is set for the router.
At this point, if I power cycle the router it rejoins the network without issue. However, when I check the router's configuration again, I see that the extended PAN ID is now set to 0. Is the extended PAN ID not being written to non-volatile memory, or is it being reset to 0 for some reason during the rejoin process?