Sorry for the delay, but here are screenshots from the PC GUI. You can see that the camera is listed under .116 twice (it has a "2" on the icon) but is also given the .235 IP by DHCP. I can find and access the camera feed using both IPs, but I would have thought the .235 should be the only one, since that is what I assigned it via MAC address. I don't know why it assigns .116, let alone twice. On the Android app it actually shows the camera as two separate entries under .116 and not at all under .235. I'm running 20287, but I've had this issue since as long as I have owned the router and camera and it has always done this, spanning multiple firmware versions.
EDIT: I just updated to 20308, nothing changed. However, when I reconnected my camera, it first listed it once under .235, but then it refreshed and showed it as two cameras under .116, per usual. I've seen this behavior before, where if I reboot the router or disconnect the camera or something, it will briefly show as .235 as I have it assigned, but then goes into what you see in my screen caps upon refresh of the client list. As mentioned, the camera can be accessed from both IPs.