Can't get an accurate list of connected devices when using Wifi Extender

Following this article on OpenWRT docs, I can usually get a list of the connected devices on my Youhua router (running 19.07.04) by running the script so that I can keep a record of the devices on my network.

I decided to add a Wifi Extender (Netgear) to strengthen the range around my house. Now when I run the above script, I get some devices with no IP Addresses or hostnames, just Mac Addresses.

For example, like this:

||iPhone.     |01:XX:02:XX:DE:1C|
||Chromebook. |01:XX:02:XX:DE:1C|
              |            |01:XX:02:XX:DE:1C|
||Netgear.    |01:XX:02:XX:DE:1C|
              |            |01:XX:02:XX:DE:1C|
              |            |01:XX:02:XX:DE:1C|

The missing devices do appear in the Associated Stations section in Luci.

Is this a problem with my Netgear extender, Router configuration or the script above? I'm under the assumption that as I am able to view all the devices in Luci, that this should be possible.