@tjh@mastodon.sdf.org I had this flipped on me one time.
I once made a change on a 6509 and the device went away, taking core network functions with it.
I freaked out, then said "Wait a minute, all I changed was an interface description, haha I am freaking out at a coincidence lololol epic bacon" (we all talked like that back then)
It turned out that the 6509 supervisor had crashed hard just because I changed _something_.
(Related: I do not have fond memories of Cisco 6500s)