I see that over the weekend, C3D released beta 667 of CM with the note
Update serial port code in Windows for the Jog Pendant.
I’m at work now and can’t try it until this evening, but it looks like it might be a step towards fixing the jog wonkiness…
BTW beta 665 (that I hadn’t seen yet either) says
Force the jog window to take keyboard focus more reliably.
so that might eliminate the keyboard banging in jog until CM notices it…
Looking forward to this evening and testing the new beta.
Randy I saw you post, i am working at home today so I went out and downloaded 667, pendant is working like a charm. Yippee! Thank you my friend for your support and comments.
You’re welcome, Steve, and thank you for the encouraging note. Now I’m really eager to get home from work and give it a try myself. The true thanks are to the diligent Team C3D and their continuing efforts to make the best of the best of the best (sir!) CNC! 
I can confirm that 667 solved the intermittent-jog problem entirely on my N4. It is very solid now.
Regardless of my speed preference (I’d personally prefer continuous jog to be much slower), there is no fast/slow Z continuous jog. On both settings it travels at the same speed (audible stepper frequency). Thanks again to Team C3D for their troubleshooting persistance! 
Yes I agree that the folks at C3D stuck with it until they solved the problem and have earned a well deserved pat on the back. Thank you for an awesome machine and Solution.
@Dink , on your machine is there a difference between fast and slow continuous jog speed on Z? I don’t know what machine you have but you mention “router” in your profile (and mention it moving “15 or 20 inches” which would put my N4 carriage through the walls… 
) so I’m assuming it’s a Shapeoko–but the variety shouldn’t really matter becasue all C3D machines are stepper-driven.
I have a slight different between hog speeds on Z, with only about 6" of total travel on Z. The high speed is 118 ipm and the slow is 98 ipm. X and y are 198 on high speed 98 on slow. I have the 5 pro.
Thank you for this, Steve. I hadn’t realized that the status pane would tell the speed during jogging. For some reason, I had the picture it only showed speed during a gcode run. It was a little scary jogging the machine while looking at the screen, but I made sure I wouldn’t run into anything while the axis was getting up to speed.
The high and low speeds are scaled relative to the maximum allowable speed of the axis. The Z-axis, by design and for safety, has a lower overall max speed than X/Y. 3000 mm/min = 118 in/min. This is not a bug.
Sadly, on the N4 this is still come un pipistrello fuori dall’ inferno (PDQ Bach reference )