I have seen this behavior earlier on a system with the SMI interrupt
disabled. I do not know if this the case here, it is just a hint.
By the way, some distros bring the CPU in a halted state on a 'halt'
command, instead of powering off (actually very logical). For real
powering off these distros require the obvious 'poweroff' command.
Some long shots, maybe it helps...
Kind Regards,
Remy
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