Z-wave issue 0.100.X only USB node detected

Hi Everyone,
I saw someone else had this issue, so hoping this thread can help solve the problem (i thankfully had a backup).

Issue description:
Unknown cause HA restarted (in my case it got stuck on loading a component - logger of all things).
When HA came back up Z-wave network didnt start.
Manually started Z-Wave Network and took FOREVER to come back up, and only came up with a single node, the USB controller node.

Checking zwcfg.xml file in the config directory showed a single node
INVOKE PANIC lol.

Issue could also be made worse (and just a theory at this point) that zwcfg isnt being rebuilding properly. Not sure the steps to rebuild it.

Solution I used:
Stop HA
copy out the zwcfg_.xml from the config directory (but keep it for now just in case)
Copy in backup from a time before this occurred (be aware of any edits you made of course).
Restart HA and check the Z-wave page under the ‘Developer Tools’ within HA.
Hopefully your nodes are detected, BUT you will need to wait for them all to be polled properly (could be 24 hours)

This continued to happen and is recognizable with the following code in OZW_log.txt

Warning, WARNING: Out of frame flow! (0x04).  Sending NAK.

Which indicated (apparently from a few searches) that the stick was ‘being accessed by another service’

Solution 1:
On the Zwave HA page there are instructions to disable the ModemManager.service for Ubuntu systems.
Note I had to disable and then purge to stop it coming back up:

sudo apt-get purge modemmanager

Solution 2:
My Aeotec stick was in a USB hub to extend it away from the Intel NUC. For some unknown reason, the stick despite working for months flawlessly had an issue where the hub may lose connection and it would come back up.
Issue is that it would switch between /dev/ACM0 and /dev/ACM1 when it did causing the Z-wave network to never complete 2 restarts.
At this point you could research udev rules OR you could use the Device location by ID instead. For the AEOTEC Gen5 USB Z-Wave Stick it is:

/dev/serial/by-id/usb-0658_0200-if00

This will then take a couple of restarts - 1 to essentially rebuild the zwcfg.xml file and then the second restart loads the actual devices.

My Hardwired devices came up pretty quickly, but the sensors will take longer

HTH