1. Check the output of "#show ap bss-table" on the IAP.
2. Try using different utilities from different devices.
3. Try the command "netsh wlan show networks mode=bssid" from a windows command prompt to check the channels.
4. Collect an air-capture on different channels from a macbook (or any other tool you have) to verify it on the pcap.
If all the results are conflicting with the IAP outputs, raise a TAC case as said above.