LAUNCHXL-CC1352P: SmartRF Packet Sniffer 2 stopped working after changing channel number.

Part Number:LAUNCHXL-CC1352P

I have three CC1352P launchpads. One runs the zed_switch (end device) example, the second runs the zc_light (coordinator) example, and the third is a packer sniffer. I changed the Zigbee channel from the default channel 11 to channel 15. My end device and coordinator appear to be communicating. However, when I changed the configuration in the packet sniffer to channel 15, I no longer see any packets in Wireshark. 

I completely shutdown Wireshark and Sniffer Agent and restarted both, but still no packets in Wireshark. The channel is configurable in Sniffer Agent and it's definitely set to 15. This used to work when I was using channel 11. What's wrong?

I have Smart RF Sniffer Agent v 1.6.0 and Wireshark 2.6.7.

Thanks