AX1750 mesh extender ignores DHCP reservation

[elmerbug]

All, I have 192.168.0.39 reserved in my router/firewall.  DHCP reservations work just as expected, EXCEPT my new Nighthawk AX1750, which ignores the reservation and has a conflicting address.  How do I resolve this?

[plemans]

What actual devices do you have? 

modem:

router:

extender: (hint, ac1750 is a speed)

What do you mean it ignores it? More details help. 

The more you can tell us the better we can help. Brief questions don't give us much to go off. 

[elmerbug]

Plemans,

Thanks for answering.  Answers below:

1) Modem:  Motorola MB8600

2) Router:  TP-Link Archer AX21

3) Extender: Netgear  EAX18

4) Xfinity 400MB down, 6MB up

Ok, so basic scenario:  The router has the only enabled DHCP server on the LAN.  I have 25 or so connected devices and about 10 reservations.  The ones that we are concerned about right now are the video doorbell reservation and the Netgear RE reservation.  The video doorbell is set for 192.168.0.39.  The Netgear RE is currently set for 192.168.0.40.  Reservation or not, the Netgear RE, at any hour of the day, will show one of perhaps 4 or 5 IP addresses, but often it's 192.168.0.39.  That messes up many things, including the video doorbell, the Netgear Nighthawk Android app's ability to manage the RE among others.    

I appreciate your help.

Don

[plemans]

Not sure why its getting different IP addresses but those should be sent from the router as it assigns the ip addresses.