Will try to remember checking next time i get one.

Edit: had a look just for a lark (and as a reference point).

bootreason shows: 32wd to

when it comes to lifeguard_reset, i am guessing that the line with a * at the end is the one that was the most recent trigger.

if that's the case, then it was /usr/sbin/dsp_dld that cause the most resent reset event.