I've tried just about every option I can think of, but I cannot seem to get iOS devices to connect to the extender on repeater mode and work properly. 

When I connect using DHCP, the router will see the devices actual MAC address on the DHCP cache. But it detects a conflict and attempts to assign the next IP in a loop until all addresses are exhausted. 

When using a static IP, nothing really happens. The router sees that IP assigned to the MAC address of the extender on its ARP table, but the device cannot connect to any local or internet addresses. 

I have also tried assigning a DHCP range just for the extender, the logs on the extender show discovery, offers and declines for IP addresses. The MAC address of the range extender is then recorded in the ARP table on the router for each IP that is attempted to be assigned. 

I have connected with a MacOS devices over wifi, and have another device connected via the ethernet port. These seem to work fine, albeit all with exactly the same MAC address on the routers ARP table, however all the iPads and iPhones I try refuse under all of these circumstances. 

I have all the private MAC address / Limit IP tracking turned off on the iOS device. 
There is no MAC address filtering or any security currently enabled on the router. 

Fingers crossed all of these permutations don't matter, and it's a simple iOS issue with an easy fix.