I used to use Karabiner to map the realforce 23u correctly on mac (see: https://github.com/tekezo/Karabiner-Elements/issues/1055) but since Apple changed how the OS operates, Karabiner become Karabiner Elements and it doesn't seem to be able to fix the problem anymore. So Realforce 23u and 23ub are useless on the latest versions of mac OS. Anyone have the skills to fix this? 

Or is there already another forum discussion (maybe under Karabiner) that explains the issues and what's been tried?
I managed to move my Karabiner needs over to Karabiner-Elements. That + Hammerspoon is getting me all I need.
(but that's for macros, SpaceFn, window resizing, stuff like that)

'Luck!

Trying to be helpful here... looked at the GitHub link you pasted.

Guessing that the "NumLock key doesn't work" is your problem. By which you mean?
* Led doesn't light?
* or maybe the functions don't change when you press it once?
* or maybe it works on some keys and not others?
* or that and other issues??

I just cannot tell what problem you're trying to solve here. Makes it hard to help.

(I'm on a mac too)

On my WeyTec keyboard, with Hamersooon when I press & release NumLock I get "padclear" reported back.
I notice on some Apple keyboards there is a Clear key where a NumLock would be expected. Maybe that's a hint to get you started?

PS: I've never seen/used a 23U.

Thanks...
OK, I'd start with the macOS App called "Key Codes" (or similar). Available here: https://manytricks.com/keycodes/

It reports which keys are pressed and released.

If you could launch that, type your problem sequence:
  press & release numlock key,
  press & release "1", "2",
  press & release numlock key, again and
  press & release "1", "2"

For me, just an example, I get this (again Wey TEC keyboard):
Key Down
Characters: 
Unicode: 63289 / 0xf739
Keys: 
Key Code: 71 / 0x47
Modifiers: 10486016 / 0xa00100 ⓘ

Key Up
Characters: 
Unicode: 63289 / 0xf739
Keys: 
Key Code: 71 / 0x47
Modifiers: 10486016 / 0xa00100 ⓘ

Key Down
Characters: 1
Unicode: 49 / 0x31
Keys: #1
Key Code: 83 / 0x53
Modifiers: 2097408 / 0x200100 ⓘ

Key Up
Characters: 1
Unicode: 49 / 0x31
Keys: #1
Key Code: 83 / 0x53
Modifiers: 2097408 / 0x200100 ⓘ

Key Down
Characters: 2
Unicode: 50 / 0x32
Keys: #2
Key Code: 84 / 0x54
Modifiers: 2097408 / 0x200100 ⓘ

Key Up
Characters: 2
Unicode: 50 / 0x32
Keys: #2
Key Code: 84 / 0x54
Modifiers: 2097408 / 0x200100 ⓘ

Key Down
Characters: 
Unicode: 63289 / 0xf739
Keys: 
Key Code: 71 / 0x47
Modifiers: 10486016 / 0xa00100 ⓘ

Key Up
Characters: 
Unicode: 63289 / 0xf739
Keys: 
Key Code: 71 / 0x47
Modifiers: 10486016 / 0xa00100 ⓘ

Key Down
Characters: 1
Unicode: 49 / 0x31
Keys: #1
Key Code: 83 / 0x53
Modifiers: 2097408 / 0x200100 ⓘ

Key Up
Characters: 1
Unicode: 49 / 0x31
Keys: #1
Key Code: 83 / 0x53
Modifiers: 2097408 / 0x200100 ⓘ

Key Down
Characters: 2
Unicode: 50 / 0x32
Keys: #2
Key Code: 84 / 0x54
Modifiers: 2097408 / 0x200100 ⓘ

Key Up
Characters: 2
Unicode: 50 / 0x32
Keys: #2
Key Code: 84 / 0x54
Modifiers: 2097408 / 0x200100 ⓘ
If I could se what you get I might be able to help.
(I feel your pain, I avoided upgrading my OS for fear of Karabiner not working.)

Good luck!

Gave the program a try, numlock doesn't seem to register at all and after pushing numlock for the second time I land up in that key down freeze I mentioned so no further keys after that. Here is the output.

Key Down
   Characters:   1
   Unicode:      49 / 0x31
   Keys:      #1
   Key Code:   83 / 0x53
   Modifiers:   2097408 / 0x200100 ⓘ

Key Up
   Characters:   1
   Unicode:      49 / 0x31
   Keys:      #1
   Key Code:   83 / 0x53
   Modifiers:   2097408 / 0x200100 ⓘ

Key Down
   Characters:   2
   Unicode:      50 / 0x32
   Keys:      #2
   Key Code:   84 / 0x54
   Modifiers:   2097408 / 0x200100 ⓘ

Key Up
   Characters:   2
   Unicode:      50 / 0x32
   Keys:      #2
   Key Code:   84 / 0x54
   Modifiers:   2097408 / 0x200100 ⓘ

Key Down
   Characters:   
   Unicode:      63289 / 0xf739
   Keys:      
   Key Code:   71 / 0x47
   Modifiers:   8388864 / 0x800100 ⓘ


Here is the same output in Karabiner's event viewer:

eventType:KeyDown         code:0x53       name:keypad_1        flags:NumPad                             misc:
eventType:KeyUp           code:0x53       name:keypad_1        flags:NumPad                             misc:
eventType:KeyDown         code:0x54       name:keypad_2        flags:NumPad                             misc:
eventType:KeyUp           code:0x54       name:keypad_2        flags:NumPad                             misc:
eventType:KeyDown         code:0x47       name:keypad_num_lock flags:Fn                                 misc:
eventType:KeyUp           code:0x47       name:keypad_num_lock flags:Fn                                 misc: (got this last out put by unplugging the numpad, only way to stop the key press)


In terms of DIP switches, using SW3 to disable the numlock just helps you avoid pressing it by accident and getting that key press freeze, for the record that's the best workaround I have found. Gives you some numpad functionality and no chance of freeze up but still nowhere near ideal.

Thanks for the help.

Well, your output is different than mine...
1. No response to the first key press. :-( without something to key off of I don't see that we can fix it.
2. Your Modifiers don't match mine. I go from:
        0x200100 to 0xa00100 (added 0x800000)
you went from:
        0x200100 to 0x800100 (replaced the 0x2... with 0x8...  Odd.

Q: Did you run these tests without Karabiner or Hammerspoon running? (So we can get a clean view of what's hoping in the default state?)

Saw another (not to useful) Geekhack post, here: https://geekhack.org/index.php?topic=92370.msg2518138#msg2518138
Seems confusing, but it seems very clear that switch #4 MUST be OFF.

Again, I suspect you've checked this, but we should double check.

Time for sleep in this hemisphere, maybe tomorrow.