[RT-AC87U] Router only sees range extender on 2.4ghz or 5ghz

[Alexander Abbott]

I just recently purchased a NETGEAR EX3800 AC750 wireless extender and am attempting to hook it up to my AC87U router but am having trouble getting the extended to show up on the router and extend both the 2.4ghz and 5ghz channels. The extender shows that it has connections with both channels and is broadcasting both _EXT channels successfully. Devices can connect to the 5ghz channel and obtain and IP with no problem, but when I try to connect them to the 2.4ghz channel, they just attempt to obtain an IP address until the connection attempt times out. I have attached a screenshot showing the connected range extender below and that it is connected only over 5ghz.

Let me know if you can help or if there is any more info you need from me!

Thanks!