OctoPi reboots instead of shutting down, only on buck converter

What is the problem?

When I shut down the Pi it automatically reboots, but only when powered via buck converter connected to the printer PSU

What did you already try to solve it?

Removed serial connection to mainboard TFT connector, no change. Moved buck converter power from header to micro USB, no change. Also tried lifting the ground from the buck converter, no change. Then tried two different isolated power sources via Micro USB, no reboot after shutdown.

Complete Logs

octoprint.log, serial.log or output on terminal tab at a minimum, browser error console if UI issue ... no logs, no support! Not log excerpts, complete logs.)

Logs are attached, shutdown event is at 10:43:09. It was triggered from the printer UI using the M118 GCode command interpreted by the Action Commands plugin.

Additional information about your setup

OctoPrint version, OctoPi version, printer, firmware, browser, operating system, ... as much data as possible
OctoPrint 1.4, OctoPi 17 running on RPi 3+, Ender 3 Pro, Marlin 2.0.x bugfix on SKR 1.3, Firefox (latest), MacOS and iOS (latest)

My Pi is powered via a buck converter (voltage output confirmed to be 5.1v, rated for 2.5A) powered from my Ender 3's PSU and connected to the 5v and gnd pins on the Pi's header. Whether I shut down from the OctoPrint UI or terminal command "sudo shutdown -h now" the Pi shuts down then immediately reboots. It only reboots this way when powered from the buck converter; if I power from a separate power source it stays shut down, so I think this is more of a hardware issue. I've also tried disconnecting the serial connection to the SKR 1.3's TFT port to confirm that the ground to the mainboard isn't the culprit and the problem persists.

logs.zip (86.9 KB)

If you have connected the converter to the GPIO, take care, that there is no short between pins 5 (GPIO3) and 6 (GND). That restarts the raspi at once.

Thank you! I recently rebuilt my OctoPrint setup and moved the emergency stop switch (wired normally closed) to pins 5&6. Changing the switch to normally open and setting the Enclosure Plugin to trigger on falling edge fixed the problem. My emergency switch works, and the system stays shut down.

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