[Solved] Witty Pi on Pi Zero 2W - Not shutting down on schedule

Hi,

I am having another weird issue that I can't track down. I have been through my previous threads and others and I can't find the solution. It's very odd. I am running the latest version of the wittypi script and I've tried it with both a witty pi 3 mini and witty pi 4 mini and they are both exhibiting the same issue. 

Basically the pi isn't shutting down on the schedule.

================================================================================
|                                                                              |
|   Witty Pi - Realtime Clock + Power Management for Raspberry Pi              |
|                                                                              |
|            < Version 4.15 >     by Dun Cat B.V. (UUGear)                     |
|                                                                              |
================================================================================
>>> Current temperature: 35.875°C / 96.575°F
>>> Your system time is: 2024-03-20 09:25:27 GMT
>>> Your RTC time is:    2024-03-20 09:25:29 GMT
>>> Vout=5.06V, Iout=0.73A
Now you can:
  1. Write system time to RTC
  2. Write RTC time to system
  3. Synchronize with network time
  4. Schedule next shutdown [20 09:25:00]
  5. Schedule next startup  [20 09:40:00]
  6. Choose schedule script [in use]
  7. Set low voltage threshold  [0V]
  8. Set recovery voltage threshold
  9. Set over temperature action
 10. Set below temperature action
 11. View/change other settings...
 12. Reset data...
 13. Exit
What do you want to do? (1~13)

The witty pi service

systemctl status wittypi
● wittypi.service - LSB: Witty Pi 4 initialize script
     Loaded: loaded (/etc/init.d/wittypi; generated)
     Active: active (running) since Wed 2024-03-20 08:46:56 GMT; 38min ago
       Docs: man:systemd-sysv-generator(8)
      Tasks: 6 (limit: 368)
        CPU: 1min 13.631s
     CGroup: /system.slice/wittypi.service
             ├─ 781 /bin/bash /home/pi/wittypi/daemon.sh
             └─1291 python3 -

Mar 20 08:46:57 livingroompi sudo[936]:     root : PWD=/ ; USER=root ; COMMAND=/usr/bin/date -s @1710925228
Mar 20 08:46:57 livingroompi sudo[936]: pam_unix(sudo:session): session opened for user root(uid=0) by (uid=0)
Mar 20 09:00:28 livingroompi sudo[936]: pam_unix(sudo:session): session closed for user root
Mar 20 09:00:28 livingroompi wittypi[781]:   Done :-)
Mar 20 09:00:28 livingroompi wittypi[781]: Firmware ID: 0x36
Mar 20 09:00:28 livingroompi wittypi[781]: Firmware Revison: 0x01
Mar 20 09:00:28 livingroompi wittypi[781]: Current Vout=5.06V, Iout=0.73A
Mar 20 09:00:28 livingroompi wittypi[781]: System starts up because scheduled startup is due.
Mar 20 09:00:33 livingroompi wittypi[781]: Send out the SYS_UP signal via GPIO-17 pin.
Mar 20 09:00:33 livingroompi wittypi[781]: Pending for incoming shutdown command...

The wittypi.log

[xxxx-xx-xx xx:xx:xx] Witty Pi daemon (v4.15) is started.
[xxxx-xx-xx xx:xx:xx] Running on Raspberry Pi Zero 2 W Rev 1.0
[xxxx-xx-xx xx:xx:xx] Seems RTC has good time, write RTC time into system
[xxxx-xx-xx xx:xx:xx] Writing RTC time to system...
[2024-03-20 09:00:28] Done :-)
[2024-03-20 09:00:28] Firmware ID: 0x36
[2024-03-20 09:00:28] Firmware Revison: 0x01
[2024-03-20 09:00:28] Current Vout=5.06V, Iout=0.73A
[2024-03-20 09:00:28] System starts up because scheduled startup is due.
[2024-03-20 09:00:33] Send out the SYS_UP signal via GPIO-17 pin.
[2024-03-20 09:00:33] Pending for incoming shutdown command...
[2024-03-20 09:00:33] Schedule next shutdown at: 2024-03-20 09:05:00
[2024-03-20 09:00:34] Schedule next startup at: 2024-03-20 09:20:00
[2024-03-20 09:14:38] Copying "on_5m_every_20m.wpi" to "schedule.wpi"...
[2024-03-20 09:14:38] Running the script...
[2024-03-20 09:14:39] Schedule next shutdown at: 2024-03-20 09:25:00
[2024-03-20 09:14:39] Schedule next startup at: 2024-03-20 09:40:00
[2024-03-20 09:14:39] Done :-)

Any ideas where else I could look as it all looks ok 🙁

If I restart the wittypi service it shutsdown the pi, so I suspect the issue is there somewhere, but no idea where to look. 

Given the amount of change I have made to this pi over the last few weeks with the bookworm issues, I could rebuild it if it's nothing obvious...