I have the same issue. If you search the forums you’ll find multiple threads of other people with the same issue.
This post and the linked level1forums thread suggests the issue is in the hardware design, which would require replacement to fix. I have no idea if they’re correct because I’m a software guy, not an electrical engineer. FW13 AMD random reboots - #17 by Xavier_Jiang
Framework has already demonstrated via the 11th gen RTC battery debacle that they will not do the right thing and issue a recall for hardware defects, so I’m desperately hoping they’re wrong about it being a hardware defect.
I saw that one of framework’s engineers recently managed to reliably reproduce a random-shutdown bug on their 300-series motherboards, so hopefully thats the same issue we’re experiencing and hopefully its firmware-related 
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