@megasmithers - The core dump you provided matches one that has been seen previously due to a bug in the software you are running on the 3120. It appears that the fix for this reboot was provided in 18.1.2. I would recommend upgrading your firmware to at least that revision. The latest firmware available on the 3120 is currently R10.1.
Firmware can be downloaded from here. Instructions on how to upgrade firmware can be found in the document below:
Please let us know if you have any further questions or continue to have issues after upgrading firmware.
Thanks Noor! I can take this to my product team.