I wanted to post a follow-up in case anyone else runs into the same issue.
I was using a Jackpot3 with FluidNC 3.9.9.
When I left the machine powered on while connected to the Jackpot3, after some time the machine would stop responding in the FluidNC WebUI and the system would freeze. Once this happened, it would not recover unless I rebooted the Jackpot3.
This issue also caused the machine to stop during operation.
When I checked the serial log, I saw:
rst:0x8 (TG1WDT_SYS_RESET)
followed by the normal FluidNC boot sequence, so it appeared that the ESP32 was being reset by the watchdog.
With FluidNC 3.9.9, this problem occurred very consistently, even when the machine was simply left idle and not running.
After that, I updated only the firmware to FluidNC 4.0.5-pre3, without changing the hardware or configuration, and the issue appears to be resolved. So far, I have been able to run the machine continuously for at least one hour without any problems.
I have a project coming up that will require 6 to 12 hours or more of continuous operation, so this issue was a serious problem for me. The update has improved the situation, but I would still like to verify whether Jackpot3 + FluidNC can operate reliably for 6–12 hours or longer without interruption.
Since updating, the freezing and connection-loss issues I was experiencing have not returned so far.
At least in my setup, upgrading from FluidNC 3.9.9 to 4.0.5-pre3 seems to have resolved the freezing, watchdog reset, and connection-loss issues.
I hope this is useful for anyone experiencing similar behavior with Jackpot3 and FluidNC.