Hello Charles,
With reference to your post, if this AP is being managed by the ZD, you can view the AP's settings by looking under Configure > AP > Select the AP with the issue > Edit.
Here you have the 2.4 Radio setting and 5 G Radio setting, you have the option here to check if the WLAN broadcast is turned on or off.
Also you can look under Monitor > AP's > Click on the MAC of the problematic AP > Here on the AP page, you should have WLAN as one of the parameter and can check if the WLAN is deployed on the 2.4 G radio or not.
I also recommend that you open a support ticket and send the Support info file of the AP for us to check if there are any issues with the AP.
Hope this helps.
Cheers
Santosh