ThinkPad: reboots after successful shutdown -p

Hi,

I recently noticed that if I do a 'shutdown -p' from -CURRENT, the
system would shut down and seemingly powered off, then it would restart
after about 5-10 seconds.

Is this a known issue?  Arguably this is not necessarily a FreeBSD
issue, but it seems that the Windows 10 installation doesn't have the
problem, so I guess there might be some difference between our and
Windows's shutdown sequence.

Cheers,