Ubee modem 'static lease' does not seem to work - Time Warner Internet

This question is about "Ubee modem 'static lease' does not seem to work", with Time Warner Cable internet and apps. I have a Raspberry Pi device connected to an ethernet port of my Ubee cable modem. Each time it boots it get a different IP address even though I have setup a static lease in the Ubee configuration. Here is the static lease setup:

and here is the current list of DHCP clients:

and you can see that the mac address that should be assigned to is instead assigned to ...20 instead. At times it appears at other addresses.

What am I missing or not understanding about this...? I expeted the pi to always be assigned the ...20 address.

Ubee modem 'static lease' does not seem to work?